When we have a member A with UDP transport with a fixed bind_port (e.g. 5000), and we restart A, then A and A' (the old A) have the same bind address and port. Therefore if another member still has A' in its view, unicast messages to both A and A' will be received by A' !
SOLUTION: if a unicast message, check the message's destination against our local address and drop the message if they don't match. If a shared transport is used, do this check in TP$ProtocolAdapter.