I think it is because you have snap turned on. It is trying to snapping to the face/vertex you are trying to bool in to.
I turned off snap, selected your Cutter.002 object in object mode, and slid it down on the Z axis. Then to fix the edge, in Edit mode select all, hit ALT+N and “Recalculate Normals Outside” and it will fix those weird edges.
also the thing you are booling with is huge:
consider this:
