agreed. can’t see it moving at all after that.
Put some exhaust sealing putty on the threads, spin on lock washer and nut and tighten, then start and run motor to cure the putty. shit hardens like rock and locks the threads.
Not the greatest way to do it, but far easier than welding and alot cheaper than spending $80 on a minute bottle of ultra temp thread locker.
Or double nut it as suggested if there’s enough thread to do so.