I can see the problem now - it's the org.jboss.weld.context.AbstractConversationContext.destroy() method. It should be revised carefully.

I'm not for overriding the cleanup() method and adding removeState() there, mainly because cleanup() contract is not defined - e.g. it's not clear when is this method called. On the other hand, a managed context should be always deactivated. The truth is there are special cases like AbstractConversationContext.destroy() where the contract doesn't matter