There's definitely some glitches with the AI. Yesterday I saw an Axis soldier with the Paratrooper rifle in the window shooting at me. I whipped out the Mauser, zoomed in, and put one right between his eyes. Nothing happened. I started pumping Mauser shots at him and it just didn't register. After that, I started having fun and tried any weapon that would reach across the partially destroyed Venom factory, still nothing. The whole time, he could shoot and register hits against me. I did a game save, and tried again. Whenever he stood in this one area, I couldn't hit him. If I drew him out, no problem. I only wish I had the Panzerfaust to see if he could have withstood that.
I've also noticed that if I turn my back on some Axis soldiers before they start shooting, I can cruise right up to them walking backwards. As soon as I turn and see them, they start firing. I've never been in a war, but I would imagine that I'd get my a$$ blown off doing that stunt.