Yes something must have changed. Replicate problem and tell us more.
A possible issue can be that the BNO bricks itself. Happened to me a couple of times, changed the BNO and no issues after that.
how can you tell if this is happening?
I noticed that the ROLL is stuck at the same angle. Check maybe if the roll direction is correct as well.
Open the steer chart and look what values your WAS is giving. When you are standing still is the value constant? Mine was jumping and this was reason why I also could not hold the line. After I changed the WAS to a different type the problem went away. Although I get ± 2cm now. I noticed that if you have a play in the steering rods or the steering knuckle (bearings or bushes) then also your WAS reading is not correct.
These are few things to check out.