Originally Posted by jtaylor996

The screw isn't backing out, as far as I can tell. I think the plastic sole between the blind nuts and the cleat is maybe deformed now, and it's slipping "downhill". The cleats have sharp serrations, and I think those have dug a little hole, and it slips into the hole. But I don't think the screw is loose at all. It's an MTB, so mud is like natural locktite.