What I expected to happen is documented
You might have a bug, either in JBoss or the documentation. BUT...
Make sure you double check your config and compare with examples. More often than not, you are not doing what you think you are doing.
Make sure you enable TRACE logging to check for strange behaviour. The logging will tell you what is happening, rather than what you think is happening.
Try to create a simple unit test to reproduce the problem. Just trying to recreate the problem in different code can point out the problem in the more complicated real code or configuration.