WFLYCLWEBUT0001 for server-side invalidated sessions

Attached is a simple webapp (pardon the name) with a single servlet "/main", that does the following:

• a session is assigned (or created, if none existed before)
• its details are printed and the browser is told to refresh after 20 seconds
• before the browser refreshes, the session is invalidated server-side by separate thread.

Expected behaviour is, that WF should give the user a new session. That's indeed how it works in standalone mode and without <distributable/> in web.xml. But in domain mode, OR with <distributable/> added (and, possibly, full-ha profile chosen), I get errors:

• The first stacktrace happens when the thread invalidates the session.
• The second stacktrace happens, when the browser refreshes. The user sees "Error 500".
• Then, after a minute or so, I get the last one. It then repeats periodically.

We can't upgrade from 10.0 because of this - and we know we need an upgrade because of fixes in Infinispan.