I had a few feed issues like this with my P10C early on. Once it was broken in, not a problem anymore. It does tend to pull the next round forward noticeably when it returns to battery. It hasn't caused a problem, but I've noticed it when dropping a partially loaded mag, sometimes the top round will fall out. I need to polish the center rail on the slide, but keep forgetting. I think a fully loaded mag introduces just enough extra drag to slow the slide down. I typically load one less than capacity though, an old habit to eliminate mag rattle in my P-01.
