This appears to only happen in a multi-threaded environment with 1 thread for send, and 1 thread of receive, and using a very short timeout for RPMessage_recv.

Currently using: LOOP=1;while [[ $LOOP == 1 ]];do ipc_test -s -m -t 0 -n 100 -v > /tmp/log.txt;echo 1;if [[ $? != 0 ]]; then LOOP=0; echo "failed at $(date)";fi;done