I have recently swapped my carry gun from my Shield 9mm to a Shield Plus 9mm, and have been having an odd problem. Every so often the 10 round magazine falls out of my holstered pistol without me pressing the mag release. The mag drop had only happened when I am seated; usually in my wife's car with its overstuffed seats. I am using the same IWB kydex holster on my right hip as I used with my Shield, and that holster 'mostly' covers the mag drop button. At first, I thought that I might be carrying the holster a bit far back on my hip and that the mag bottom was pressing into the seat back and being released. I have been keeping the pistol forward more and canted a bit further forward. However, every so often I find the mag lying on the car seat when I get up, and today the mag dropped onto the floor today while I was laying back in my dentist's chair. The dental assistant returned the mag to me without any comment. In any case, the mag drop issue is making it hard for me to trust the pistol. Has anyone else run into a similar issue? Any other ideas that I can try? Thanks