I have a dozen 15 round KCI mags for my G19 and have not had a single issue with any of them through at least 5k rounds between them all. The single 33 round mag I have is a POS though, both to load and malfunctions.
Zero issues with the 3 Elite Tactical Systems 31 round mags I have for my G19 Sub 2000 with a few hundred rounds through each of them. I presume that they'd work for your ATI.
I had some of the original KCI mags and the 15 round mags were ok but the 33 round had a two piece metal liner. Not long after that I got some factory new Glock 33 rounders for $20 each and never looked back.