Airplane bouncing when loading a flight

Hi,

I have a couple of saved flights that, engines started, airplane ready to go.  When I load them, the airplane bounces around rather violently...sometimes I hear "Bank Angle" and then settles down...usually somewhat askew of where I parked it and does the countdown.  Autopilot is not engaged yet.  Any idea what would be causing it?

I tried a few different things and....sounds weird, but...on my limited tests it only seems to happen on the Southwest Airlines livery.  The other two I've tried (default and British Air) it's fine.  All I did was save the flight with one of these liveries and restart it and the problem was gone.