Factory magazines have a convex style follower,as different from
standard flat.This and the guide edge geometry certainly affects
the rounds loading position and may cause them to fail to load.
But it is unlikely that the slide will freeze 1/2" from battery because
the magazine follower is somewhat incompatible with the pistol.
If the rounds are stuck in the chamber then it is a different issue
I think what we are discussing here is a sudden interruption in the
slide travel during what otherwise might have been a normal cycle.