More than likely this is what is going on.
Bolt open and back. Transitioning positions shooter tips rifle down going into the prop. Bolt slides forward and bounces round into chamber as bolt stops on the magazine. Shooter goes to push bolt forward and round is in the chamber.
Brings out knife to the rescue. Cycles bolt and all is good.
Be conscious of your rifle manipulation in and out of props to prevent this. You can add a rubber band, bungee cord or place thumb on bolt when moving. I place my thumb on the bolt when moving positions. Once you realize it is a SUPER slick action and not much of a tip when moving will cause this. You as a shooter move smoother and better after a couple afternoons of practice. it's not the rifles fault. its the shooters fault. We as shooters are the last to blame ourselves for issues on the range.
I have been there done that. learned the lessons and shoot better for it.