Hi Thalamus,
I tried but it wasn't the solution. Untagging the "Filter Mechanical Plunger" the only change I got was the little but continuous movement of the plunger.
Aniways, I investigated more the issue and I finally discovered what it was.
The Ramp10 had the material set to "_Metals",
Looking to the the physics of that material, I seen that it has elasticity of 0.2 and scatter angle of 5.
Don't ask me why, but with my cabinet those numbers does crazy things to the ball movement.
For example, in case I leave those values for the table surface, when the ball is fired away by the slingshots it behaves as if there was some strange forces which made it take unrealistic paths.
I set the ramp and the plunger to the values highlighted in red in the images attached here below and everything works great now.
Note that I moved the plunger ahead just because I like to see the moving even if the plunger is pulled very little, it has not really much to do with this issue.
I also changed the table inclination from 8 to 24 to see the B-E-T lanes and their lights.
BTW, if I check this issue with my desktop the issue never happen. I've no idea about how elasticity and scattering are applied to the simulation, but it looks like as that when the PC is slower they are omitted
Thank you for your interest about this issue.
Have a great day
Massimo