Yup, I've encountered the dreaded "double feed" w/ two live rounds, malfunction.
It started occurring with 7-rnd Checkmate magazines with the hybrid feed lips. These magazines were reliable for a year or two, then the double feeds started. Traced it back to the feed lips spreading.
IMHO, the hybrid feed lip design is more susceptible to spreading then the parallel design.
Switched over to Tripp Cobra magazines and have not had a double feed since the change.