Mag won't lock in place, neither did the replacement - Mec-Gar USA Inc Magazine Ruger Mkiii 22/45 Model .22lr 10 Round Blued

My MKIII has doesn't have magazine issues with Ruger-made mags. The Mec-gar mag wouldn't lock in, so I returned it, but the replacement didn't work either. It took a month to send the replacement to me, so Optics Planet won't accept a return for the second defective magazine. So I'm screwed.

Of note, my MKIII does have the Volquartsen Firearms Pistol Competition trigger kit installed, but I doubt that is causing the mag not to lock in place. Ruger mags work just fine before and after the trigger upgrade.