Unfortunately not, I'm not involved enough in the JCR code and JBoss Cache usage to know what exactly is going on, I just did some initial investigation to know if it was an issue with eXo JCR or JBoss Cache. And it looks like
org.jboss.cache.invocation.NodeInvocationDelegate
is not expecting a node wrapper on a null node, which seems to be
NullMarkerNodeForRemoval