I forgot to deploy a sub process and found the behavior of jBPM rather strange. There only a DEBUG line (good I had it on) saying "ProcessState - subprocess for process-state 'myname' not yet bound". And it looks like it is waiting at this point until the sub process will be deployed? I think it should be an error if a referenced sub proccess is not found?
jbpm has two options... late (runtime) binding and early (deploy time) binding with late being the default (afaik). This way the latest version of the subnprocess is always used. The first time a parent is deployed there might not be a subprocess jet, so at least (most?) a warning should be displayed..... Please file a jira issue for this and reference this topic