It's my understanding that the slide lock is supposed to engage after the last cartridge is fired, signifying so. I've noticed that my P226 lately has done this sometimes and many times fails to do this. The slide lock does however work fine and if I manually shove the slide back when the mag is empty, it locks just fine. My gun is still pretty new (I got it in June) and I'm also still pretty new to taking care of it. Is this maybe a lubrication issue? What could cause this? When I first got it, it locked back every time I fired the last round. Thank you.