My Czechmate mags suffered from this if I loaded more than 26. With CZC base pads and Grams kits they hold 28/29. I sent them to Grams who reprofiles the mags where they funnel from double to single stack. This cured the problem of the rounds not stacking directly on top of each other and nose diving.
That said, I have never had the problem on my TS .40 or CTS 9mm, both of which have CZC base pads and in the case of the TS, Grams followers.