'
What do you suppose happens when the scope slides in the rings, and the magnification ring comes up against the scope ring? It jams the magnification ring, so that it won't move.
I have never had this type of issue, but I also avoid Millet rings.
I've never had a mag ring jam, I don't know which scope would allow the rings to jam the magnification ring, but that would be a pretty weak design.
all my scopes tubes have a "protrusion" before the actual magnification adjustment so the rings cannot lock it.