I just had my outside the waistband HBE for my Kahr K9 self-eject my magazine. I found it on the bedroom carpet so there was no harm done, but leaving the release free to rub against the body seems to be a particularly bad idea. It seems to be a common design, however - my JM Custom Kydex OWB Type 1 for my G19 is the same way.
It raises a question - why is it a good idea to have the magazine release exposed and not protected by holster material?