Ditto.
I might feel different if we had some sort of robust data set instead of anecdotes, such as a large police agency adopting the 43X/48, specifying a certain generation S15 mag as part of a purchase, and there being ample evidence about its performance. Unfortunately the FAMS is piggy-backing the CBP Glock contract instead of going for a gun that seems almost purpose designed for their uses, and I don't imagine any other agency would have the possibility of becoming a customer on a significant institutional level. And, it's not like 43Xs and 48s are so popular in classes that an open-enrollment instructor is going to collect meaningful data by asking students to run instructor-provided S15 mags in classes.
A couple guys here and there across the internet with low round counts on a small sample of mags doesn't cut it for me when there's even more guys on the internet saying they've had problems.