Also, the gearing slot may be worn and not correctly aligned causing them to not properly engage the camera film advance lever for the mag on the back of the body. I believe there is also a spring on the bottom righth and side of the mag that the body trips to release the mag to allow the film to advance as the body winder is turned. If it gets bent or out of adjustment, the body won't trip the mag release.
And not to be argumentative, but perhaps you can esplain how the slots on the mag or body would be worn so as not to engage the locking prongs (I assume you mean on the top of the rear of the body).
I still think that mag needs a CLA.