CoastalDriver wrote on Apr 5^th, 2021 at 9:56am:

Guess you need to do the Boeing 'Sudden Upset' course. Rudder actuator failure or seizing was not that uncommon actually in the 737 - led to quite a few failures - always denied by Boeing - they claimed lack of crew procedure. Anyway - so AP disconnect did not restore control?

I'm aware of that problem, I mentioned it in the post. But I just did another flight and it didn't happen. The rudder changed randomly but it didn't lose control. I did unplug my hardware rudder so maybe that?