I agree that this is a problem with the design or implementation. All you have to do is look in the windows to watch the spring get all deformed as you push the follower in. You can watch it kink up, and you can feel it get in the way of the catch. It's that simple.
One of the biggest features of the Zetamag is the ability to reload it, in hand, while your loaded gun is still also in-hand. It's literally like having a third hand. Two Zetamags, a bunch of ten round tubes, and a little bit of manual dexterity will probably showcase the real potential for fast and light play with such a setup.
But we can't be doing this "jerking off" thing with the reloading rod or squeegie. It needs to work every time. Not even 90%. Not 95% of the time. 99.9999999999999999999999999999999999999% of the time.