I didn't really go messing around with, just dropped it off at PSA as there is one on my way home from my friend's farm but I'm thinking the mag wasn't seating far enough in to engage the stop. Three different mags, same problem. I started getting frustrated and didn't think to try holding the mag in place (teacup style) to see if that helped. My brother's is having the same issue with four different mags; he ran the mags through a G43MOS and they functioned fine in that gun so I'm assuming it's a gun issue. I know one other person who is having a similar issue with his; he has three mags as well, same problem. I posted something about it in one of the other Micro threads but I've noticed in some of the pictures people have posted of their guns that in some of them you can see more of the magazine body so it's apparently sitting a hair lower in the magwell.
My brother also said the accuracy on his was terrible; I sent him a link to the thread someone else posted showing their muzzle but he said his looks OK. He's planning to sell his and stick with his P365 (not sure which model).
I really like the way the gun feels, but if I get it back, shoot it on their range it doesn't shoot well I'll sell it and probably get a Shield Plus, that was my plan before the Micro came out. It sucks, I like the Micro feels, fifteen rounds, supporting a SC company, etc so I'm willing to give it a fair shake, guess we'll see.