It could help others in despair you know, like yourself previously
Very well, I've learned over time that the Poldiac switch can be rather sensitive to the tightness of the double screws in the delrin switch body. One does not want to over-tighten them, and in fact it seems best to set the pole screws into the double screws tightly and then screw them into the delrin part just tight enough to stay put, and no tighter.
I had gone through this particular Poldi again and again, swapping out every part, obsessively cleaning every part, and the one factor that finally stood out was the tightness of the screws in that delrin part. I'm still not sure why, I think it must have something to do with the alignment of the contact ends of those screws inside the switch relative to the pin in the button which needs to make contact equally with both of them to fire the mech. Over-tightening the screws in the ends seems to negatively affect this.