I mean, you should attach a remote debuger to your AS instance.
This is a pita, as you need to have all the code -- AS project has it, and we use Maven, so it's doable.
Then step-by-step, to see why the classloader from one domain actually jumps / sees the other domain, where they should be isolated from each-other.
Make sure you don't have any unneccessary jboss-classloading.xml files present, which could instruct the CL to point to wrong domain.