Which node do you redeploy when it doesn't work? the RO or the RW? anyway, I think you can add a bug report on sf.net/projects/jboss as we should support redeploy of such apps.
If I re-deploy to the RW node, cache invalidation still works fine.
If I re-deploy to any of the RO nodes the invalidation mechanism fails.
I will add a bug report as suggested (sourceforge site is down at present)