I would guess that for some reason, the brass pad ,very small, slipped out of it's proper place! I have had that happened several times! I had the plunge handle loose. If memory serves Me, there is a small brass piece (1/4 by 3/42), or close to that. It can slide out of the hole and back inside the router! I needed to take it apart, and tap the unite on a piece of wood, covered with white cloth and it fell out. Then with a tweezers, put it back in place. It rubs on the shaft, I believe, and when You release the button, it grabs the shaft. I could not tell anything was wrong by touch. It felt OK. So it is worth a try!
John 3:16 Please fill out your profile, It helps us to know you better