• Start 2 demos (Infinispan 4.1 alpha2) with runGuiDemo.sh
• Insert test=1 into A, you'll see it in B as well (numOwners=2)
• Insert test=2 in B, you'll see it in A as well
• Pull the plug on A (or B, doesn't matter)
• Wait until both A and B are in their own clusters
• Reinsert the plug
• Insert test=3 in A: this won't get distributed to B !
• Generate 50 random keys and values in either A or B: they won't
  get distributed to the other node !

As a matter of fact, nothing gets distributed anymore after pulling the plug !

Instead of pulling the plug, you can also uncomment <DISCARD.../> in jgroups-udp.xml and mimick a partition and subsequent merge this way, same effect.

Using only JGroups (e.g. Draw), this works fine.