X_DEV_STOP_TIMEOUT
Means
x stop sent SIGTERM and x dev did not exit in time
Typical cause
the x dev the checkout lock names is still running when the wait ends: a drain past its deadline, or a process that ignores SIGTERM
Fix
x stop --timeout 2m --json; still running: kill -9 the pid its cause names, then x dev --json (a hard kill leaves the lock, which the next boot clears)