Thanks for feedback.
Ok, seems to be the same issue, or at least based on the same cause.
Luckily for now - after reading https://issues.jboss.org/browse/JBSEAM-4976 I tried the proposed workaround with partial statae saving as context-param, and it seems to solve the issue for me. At least it does in my test case.. lets see if it is also for my real project. I'll try..