A flush or join shows the following type of errors:
ERROR: Error receiving IPC buffer from server: Invalid argument
ERROR: Failed to send/recv nudn Flush Only(1) request, payload_err=22
Caching Users... ERROR: Error receiving IPC buffer from server: Invalid argument
ERROR: Failed to send/recv User Flush IPC request, payload_err=22
ERROR: Failed to send Users Flush IPC, error=22
The problem is that the /tmp filesystem had the setgid bit set. This was causing the ipc credentials to be different then what vasd was expecting.
Take a look for the following permissions on directorys for example. The s indicates that setgid is set on group for tmp. Change this to 755 something else. Basically take the setgid off.