Infinispan in distribution mode does not correctly balance its data after a merge. In a cluster larger than the number of dist owners (the only reason to use distribution), some nodes can end up not owning any data. This causes errors creating web sessions in EAP, because it will only create a session with an ID that is owned by the local Infinispan cache.
Verified with EAP 6.4.17.CP.CR4
Released on 2017-09-05 as part of the EAP 6.4.17 release.