I was just shooting this evening with a guy who has a 43X I think with the steel mag button. He kept ejecting the mag by accident.
I picked up a couple of Gen 2 mags to try out a few months ago. Neither of them would lock into place when I attempted to seat the magazine. I have an OEM mag release. A buddy of mine has the Shield Arms release, and has Gen 1 mags. My mags wouldn't lock into his gun either. Shield Arms sent me replacements saying mine were from a 'bad batch'. The replacements wouldn't seat either. I took them back to my local gun store and exchanged them for more OEM mags. I'm just going to stick with OEM mags from here on out.
I have six of the gen1 magazines. They all work just fine in both of my G48s with the Shield steel mag catch.