After some troubleshooting, it seems Morblias's root issue is a corrupt USB packet which the Monarch firmware is failing to recover from without being reinitialised.

Nasser, it all starts when a WX gets a "ERR:SIGNATURE" - from that point on, all commands are considered invalid.
Edit: Or more accurately, it appears as if "ERR:INVALID COMMAND" is just being flooded back forever, with or without another command...