the mid cap mag feeding issues are not likely a magpul issue but more just a "mid cap" issue.
This is a recurring complaint and it doesn’t matter who makes them, Magpul, G&P, KA, Star, and MAG midcap mags all have the same problem.
Luckily the solution is simple as mentioned above.
The problem is happening because of lack of lubricate around and along the spring track.
If you spray some silicone oil spray in the top hole and or if possible remove the bottom spring cover to spray in that hole also.
Or remove the spring all together and give the spring a good lube.
Poor mid cap feeding issues would be one of the most common complaints we received, and after giving this solution, we are ether thanked for correction of the problem or never hear from the complainant again.
back OT i'm aware of some fitting issues with the green label.
so the regular magpul PTS pmags are probably a safer bet.
although that's not to say they don't have some fitting issues ether.
We can test mags and models if both are in stock, if need be.