So I‘ve learned 2 things tonight…
If you apply any amount of load , as Norm suggested, the “issue” goes away. Light engine is the only time the front gearbox dances around.
if you put a tiny piece of foam between the gearbox and it’s upper “stop”, the issue completely goes away. Very soft foam, so not enough to stop movement in case of shock, but enough to dampen the oscillation.
Thanks for the feedback and input guys. I’m considering this case closed (for me at least).