My cabinet has a similar problem. I'm not sure what is going on in there when the door is locked. But my wife does not believe me. Like if I put two 12 ga shotguns side by side the next thing you know a cute little 20 ga pops up out of nowhere.
Take last week for example. I put my Marlin .45-70 Guide rifle too close to my Win '94 32Spl and the next thing I know I now have a Puma .44!!
I believe I may have to put all my guns into those silicon sleeves so there is only SAFE-STORAGE going on in there when the door is shut.