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Gen3 pmag's work fine. The key is to look at the cut-out on the top rear of the mag (where the rear of the cartridge would be in a loaded mag). If the cut-out is square (or rectangular) you are good, if it is a half-moon or similar, it will have issues. TV-Presspass has a video on how to modify gen 1 and gen 2 pmag's to work around the issue.
The problem isn't specific to pmag's but those are pretty common. Just look at the back and you'll know.