Hey there.
I've got a P01 and when I finished putting it together I find that the sear doesn't drop when the slide is racked or the hammer cocked, so the hammer tilts back with the racking/cocking and slams forward the moment my thumb moves off it, or the slide comes forward. I took the upper off and I can push down on the sear and it will catch the hammer, and when I have the sear cage assembled with a slave pin outside the gun the sear sits low like it's supposed to.
Any idea what could be causing this?