It's clear we need to see the rest of the gun to figure this out. If we've inspected the Hell out of the detents, then the problem must be somewhere else. The small body scratch next to your detent is a flag.
Need to see the marker both assembled and disassembled so we can check for abnormal things, like missing field strip screw bushing, "customizations", an LX bolt which isn't really an LX bolt, and/or weird alignment which would cause the bolt to hit in a weird way.
"Accuracy by aiming."
Definitely not on the A-Team.