Picked up a p238 a couple of weeks ago. Love it, but had a few problems with extraction/ejection. At first it would sometimes fail to extract, usually the last round, but it also would randomly trap the brass horizontally between the slide and the chamber with the next round trapped underneath. I cleaned and lubed, tightened the extractor just slightly and paid close attention to my grip. Now it extracts but still traps that brass like a horizontal stovepipe. Going back over my notes I noticed that every failure (six in 100 rounds) now occurs on the fourth round of the six round mag. Does this sound like a mag issue? I only have the one that came with the gun right now, so I can't change mags to see if another would fix the issue.