Mike,

Good questions, but believe me, the fix works. The problem may result from yanking on the belts - causing the finger I mention to bend. It doesn't wear. There could also be some wear occurring on the bottom tip of the plastic seat that the lead weight sits on (the spot that contacts the finger). If all this doesn't sound clear, it will be if you look at the mechanism. Try removing the end cap, then hold the circular plate in its normal position with the reel level and arrow in the up direction. Look at the position of the finger relative to the toothed disk on the reel. You will find it is almost contacting the teeth. My suggested fix simply adds a little clearance here. If this clearance is not the problem, then as you suggest, there is a problem elsewhere.

I must state the caveat that this is a critical safety item and if in doubt, don't reinstall it. I take no responsibility for subsequent belt malfunctions or failures after applying the suggested repair.