Quoted from poup:
Leveled up the upper right leg, It happens less. The playfield protector is also one of the reason
I already removed the protector, no impact on that issue. And It's well levelled for the whole flow.
3D printing would be ideal. I have the printer but not the 3d design skill ^^
If someone is skilled enough, and as spare time, i can work with to design a prototype.