So after turning on more debug logging I'm not really any closer to resolving the issue. For successful requests (prior to restarting JBoss) I see the following log output:
[Mon Aug 27 09:19:01 2012] [debug] mod_proxy_cluster.c(1954): cluster: Found value kfgWYATYANH7eonwiuLLzShr.f261431e-7879-3c7e-9aec-f01bc9542c5d for stickysession JSESSIONID|jsessionid
[Mon Aug 27 09:19:01 2012] [debug] mod_proxy_cluster.c(2338): cluster: Using route f261431e-7879-3c7e-9aec-f01bc9542c5d
[Mon Aug 27 09:19:01 2012] [debug] mod_proxy.c(1020): Running scheme balancer handler (attempt 0)
[Mon Aug 27 09:19:01 2012] [debug] mod_proxy_ajp.c(681): proxy: AJP: serving URL ajp://wlg-mafapweb05:8009/e-cert-information/ecert
[Mon Aug 27 09:19:01 2012] [debug] proxy_util.c(2011): proxy: AJP: has acquired connection for (wlg-mafapweb05)
.....(More logging representing a successful request)
After restarting JBoss I see all of the ENABLE-APP traffic (already posted above) and the following additional debug logging when attempt to access the application
[Mon Aug 27 09:22:17 2012] [debug] mod_proxy_cluster.c(1954): cluster: Found value kfgWYATYANH7eonwiuLLzShr.f261431e-7879-3c7e-9aec-f01bc9542c5d for stickysession JSESSIONID|jsessionid
[Mon Aug 27 09:22:17 2012] [debug] mod_proxy_cluster.c(2338): cluster: Using route f261431e-7879-3c7e-9aec-f01bc9542c5d
[Mon Aug 27 09:22:17 2012] [debug] mod_proxy_cluster.c(1543): proxy: byrequests balancer FAILED
[Mon Aug 27 09:22:17 2012] [error] proxy: CLUSTER: (balancer://mycluster). All workers are in error state
Any ideas? For completeness, here's the entire log from the point JBoss is shut down - there's multiple web applications so it's a little verbose:
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans DISABLE-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler DISABLE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fuser-admin-web"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler DISABLE-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans STOP-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler STOP-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fuser-admin-web"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler STOP-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans REMOVE-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler REMOVE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fuser-admin-web"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler REMOVE-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans DISABLE-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler DISABLE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fe-cert-information"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler DISABLE-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans STOP-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler STOP-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fe-cert-information"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler STOP-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans REMOVE-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler REMOVE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fe-cert-information"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler REMOVE-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans DISABLE-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler DISABLE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fe-cert-scanner"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler DISABLE-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans STOP-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler STOP-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fe-cert-scanner"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler STOP-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans REMOVE-APP (/)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler REMOVE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fe-cert-scanner"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler REMOVE-APP OK
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1667): manager_trans REMOVE-APP (/*)
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2323): manager_handler REMOVE-APP (C:/NODE_COMMAND) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d"
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(1143): process_node_cmd 4 processing node: 1
[Mon Aug 27 09:21:33 2012] [debug] mod_manager.c(2366): manager_handler REMOVE-APP OK
[Mon Aug 27 09:21:34 2012] [debug] mod_proxy_cluster.c(678): update_workers_node starting
[Mon Aug 27 09:21:34 2012] [debug] mod_proxy_cluster.c(693): update_workers_node done
[Mon Aug 27 09:21:34 2012] [debug] mod_proxy_cluster.c(604): remove_workers_node (helper) 0 f261431e-7879-3c7e-9aec-f01bc9542c5d
[Mon Aug 27 09:21:34 2012] [debug] mod_proxy_cluster.c(678): update_workers_node starting
[Mon Aug 27 09:21:34 2012] [debug] mod_proxy_cluster.c(693): update_workers_node done
[Mon Aug 27 09:21:34 2012] [debug] mod_proxy_cluster.c(678): update_workers_node starting
[Mon Aug 27 09:21:34 2012] [debug] mod_proxy_cluster.c(693): update_workers_node done
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(1667): manager_trans INFO (/)
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(2323): manager_handler INFO (C:/) processing: ""
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(2366): manager_handler INFO OK
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(1667): manager_trans CONFIG (/)
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(2323): manager_handler CONFIG (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Host=WLG-MAFAPWEB05&Maxattempts=1&Port=8009&StickySessionForce=No&Type=ajp&ping=60"
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(2366): manager_handler CONFIG OK
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(1667): manager_trans ENABLE-APP (/)
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(2323): manager_handler ENABLE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fe-cert-scanner"
[Mon Aug 27 09:22:04 2012] [debug] mod_manager.c(2366): manager_handler ENABLE-APP OK
[Mon Aug 27 09:22:05 2012] [debug] mod_manager.c(1667): manager_trans STATUS (/)
[Mon Aug 27 09:22:05 2012] [debug] mod_manager.c(2323): manager_handler STATUS (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Load=100"
[Mon Aug 27 09:22:05 2012] [debug] mod_manager.c(1404): Processing STATUS
[Mon Aug 27 09:22:05 2012] [debug] mod_proxy_cluster.c(258): Created: reusing worker for ajp://WLG-MAFAPWEB05:8009
[Mon Aug 27 09:22:05 2012] [debug] mod_proxy_cluster.c(360): proxy: initialized worker 1 in child 1396 for (wlg-mafapweb05) min=0 max=64 smax=64
[Mon Aug 27 09:22:05 2012] [debug] mod_proxy_cluster.c(418): Created: worker for ajp://WLG-MAFAPWEB05:8009 1 (status): 1
[Mon Aug 27 09:22:05 2012] [debug] proxy_util.c(2011): proxy: ajp: has acquired connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:05 2012] [debug] proxy_util.c(2067): proxy: connecting ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:05 2012] [debug] mod_proxy_cluster.c(678): update_workers_node starting
[Mon Aug 27 09:22:05 2012] [debug] mod_proxy_cluster.c(693): update_workers_node done
[Mon Aug 27 09:22:05 2012] [debug] proxy_util.c(2011): proxy: ajp: has acquired connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:05 2012] [debug] proxy_util.c(2067): proxy: connecting ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:05 2012] [debug] proxy_util.c(2193): proxy: connected ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:05 2012] [debug] proxy_util.c(2193): proxy: connected ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:05 2012] [debug] proxy_util.c(2444): proxy: ajp: fam 2 socket created to connect to wlg-mafapweb05
[Mon Aug 27 09:22:05 2012] [debug] proxy_util.c(2444): proxy: ajp: fam 2 socket created to connect to wlg-mafapweb05
[Mon Aug 27 09:22:06 2012] [debug] mod_proxy_cluster.c(773): ajp_cping_cpong: Done
[Mon Aug 27 09:22:06 2012] [debug] proxy_util.c(2029): proxy: ajp: has released connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:06 2012] [debug] mod_proxy_cluster.c(678): update_workers_node starting
[Mon Aug 27 09:22:06 2012] [debug] mod_proxy_cluster.c(693): update_workers_node done
[Mon Aug 27 09:22:06 2012] [debug] mod_proxy_cluster.c(678): update_workers_node starting
[Mon Aug 27 09:22:06 2012] [debug] mod_proxy_cluster.c(693): update_workers_node done
[Mon Aug 27 09:22:06 2012] [debug] mod_proxy_cluster.c(773): ajp_cping_cpong: Done
[Mon Aug 27 09:22:06 2012] [debug] proxy_util.c(2029): proxy: ajp: has released connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:06 2012] [debug] mod_manager.c(2366): manager_handler STATUS OK
[Mon Aug 27 09:22:09 2012] [debug] mod_manager.c(1667): manager_trans ENABLE-APP (/)
[Mon Aug 27 09:22:09 2012] [debug] mod_manager.c(2323): manager_handler ENABLE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fe-cert-information"
[Mon Aug 27 09:22:09 2012] [debug] mod_manager.c(2366): manager_handler ENABLE-APP OK
[Mon Aug 27 09:22:10 2012] [debug] mod_manager.c(1667): manager_trans ENABLE-APP (/)
[Mon Aug 27 09:22:10 2012] [debug] mod_manager.c(2323): manager_handler ENABLE-APP (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Alias=default-host%2Clocalhost%2Cexample.com&Context=%2Fuser-admin-web"
[Mon Aug 27 09:22:10 2012] [debug] mod_manager.c(2366): manager_handler ENABLE-APP OK
[Mon Aug 27 09:22:10 2012] [debug] proxy_util.c(2011): proxy: ajp: has acquired connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:10 2012] [debug] proxy_util.c(2067): proxy: connecting ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:10 2012] [debug] proxy_util.c(2193): proxy: connected ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:10 2012] [debug] mod_proxy_cluster.c(773): ajp_cping_cpong: Done
[Mon Aug 27 09:22:10 2012] [debug] proxy_util.c(2029): proxy: ajp: has released connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:16 2012] [debug] mod_manager.c(1667): manager_trans STATUS (/)
[Mon Aug 27 09:22:16 2012] [debug] mod_manager.c(2323): manager_handler STATUS (C:/) processing: "JVMRoute=f261431e-7879-3c7e-9aec-f01bc9542c5d&Load=100"
[Mon Aug 27 09:22:16 2012] [debug] mod_manager.c(1404): Processing STATUS
[Mon Aug 27 09:22:16 2012] [debug] proxy_util.c(2011): proxy: ajp: has acquired connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:16 2012] [debug] proxy_util.c(2067): proxy: connecting ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:16 2012] [debug] proxy_util.c(2193): proxy: connected ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:16 2012] [debug] mod_proxy_cluster.c(773): ajp_cping_cpong: Done
[Mon Aug 27 09:22:16 2012] [debug] proxy_util.c(2029): proxy: ajp: has released connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:16 2012] [debug] mod_manager.c(2366): manager_handler STATUS OK
[Mon Aug 27 09:22:16 2012] [debug] proxy_util.c(2011): proxy: ajp: has acquired connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:16 2012] [debug] proxy_util.c(2067): proxy: connecting ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:16 2012] [debug] proxy_util.c(2193): proxy: connected ajp://wlg-mafapweb05:8009/ to wlg-mafapweb05:8009
[Mon Aug 27 09:22:16 2012] [debug] mod_proxy_cluster.c(773): ajp_cping_cpong: Done
[Mon Aug 27 09:22:16 2012] [debug] proxy_util.c(2029): proxy: ajp: has released connection for (wlg-mafapweb05)
[Mon Aug 27 09:22:17 2012] [debug] mod_proxy_cluster.c(1954): cluster: Found value kfgWYATYANH7eonwiuLLzShr.f261431e-7879-3c7e-9aec-f01bc9542c5d for stickysession JSESSIONID|jsessionid
[Mon Aug 27 09:22:17 2012] [debug] mod_proxy_cluster.c(2338): cluster: Using route f261431e-7879-3c7e-9aec-f01bc9542c5d
[Mon Aug 27 09:22:17 2012] [debug] mod_proxy_cluster.c(1543): proxy: byrequests balancer FAILED
[Mon Aug 27 09:22:17 2012] [error] proxy: CLUSTER: (balancer://mycluster). All workers are in error state