Hi,
i have two nodes setup in domain clustered mode, i am currently upgrading from 4.3.0 which is working fine to 4.4.0, after upgrade node1 keycloak-master starts without problems, but when i try to start node2 - keycloak-slave it fails with Exceptions related to StateTransfer of infinispan caches.
What does the other node show when the state transfer error appears in node 1? You should get a thread dump in the other node too to see if something is hanging.