Alvin,
Are you sure that your Mauser follower holds the slide back after the last shot is fired? I doubt it. I know it looks that way, viewing parts through the open ejection port, but you might find a few thousandths clearance between the slide face and follower. The way you know what's going on is if you feel slight drag when removing the empty magazine while the slide is locked open; there would probably be heavy slide spring tension on the follower, if it works the way you think it does. I suspect you will find no tension or drag.
I haven't worked on one of the early Mauser pocket pistols (.25 and also .32/.380) for a few years, but my Mauser HSc uses basically the same slide lock system, which I am still trying to figure out; even after disassembling it and staring at the innards many times. I'm still relatively new to working on the HSc mechanism.
Try this and you may be surprised. Close the slide and remove the magazine. Draw the slide back. I think you will find it will lock open, with no follower or magazine body touching anything. This is how my HSc works. Insert the magazine, empty or loaded, and of course the slide will release.
Here's a little Mauser pistol trick an experienced gun guy friend of mine told me about recently. You can release the locked back slide without inserting a magazine. In that mode, magazine removed and slide back, grasp the slide serations and
very quickly and sharply draw it back and release it; in a split second. The slide will close. I have no idea why this works, but it does. And you don't grind up your mags all the time just to release the slide.
I don't like any part of this Mauser slide lock system, but the HSc has other strong points, which make me like it almost as much as a PPk, now that I built a couple springs and ammo to make it reliable.
It is worth noting that, to my knowledge, no other manufacturer has felt there was customer demand for incorporating this slide lock system into any other pistol design. Kind of like the toggle bolt.
So for those of you who hate those silly toggle bolts, I'm accepting donations of all pistols using this obsolete mechanism.