I have a 19c that after 200+ rounds or so suffers from a goofy hiccup. Sometimes when it gets dirty, if I have the mag out and I rack the slide back it will lock back without touching the slide release. If I smack the backplate it slams forward and sometimes it won't lock but I can feel it stick back like it wants to when I cycle the slide. The range officer at my go to range says he has seen this before but can't pin point the cause.. When I clean and oil the barrel and frame, it won't do this but if I shoot 200 or more rounds it will happen recurringly. It's annoying but it's never happened with rounds in the chamber or caused a misfire.. Has anyone seen this issue before? And if so, what is the underlying cause?