Okay this just started in the last month and I have owned the gun for three years now. When I have the selector set to fire the top bbl first after the shot the gun will come unlocked. The first time I noticed it I was shooting heavy 3 inch shells and I thought my thumb hit the lever under recoil. Today rabbit hunting with light loads it did it again twice in a row. My FIL told me to move the selector to the bottom bbl and leave it there. Shooting the bottom bbl first it never did it the rest of the day.
How do I fix this? It is a waterfowl model with 3.5" chambers and camo dipped FYI.