The points are angled. The rims of the cases rest on the angled surfaces, wearing into the aluminum. at a certain point in the wear, the rims, when in the grooves worn into the loader points, won't allow the points to turn. I have a halfdozen or so that this has happened to, some would not release the rounds at all, unless the loader was turned upside down to let the rims come back out of the notches in the loader points, and some were beginning to get sticky in releasing. Inspection revealed they were wearing, so I retired them.
If you doubt me, I will mail them to you, and you can try them. They are sitting in a drawer gathering dust. I'm not even interested in having HKS replace them (even if they would). I have switched to Safariland loaders and like them much more than the HKS loaders. I'll probably just throw them away unless you want to see them.
I've always carried the HKS loaders in the HKS belt carriers.