I just encountered this as well.
Found two RAK magazines and one CR75 magazine in the police station in Krasnostav. It seems that the magazines will show as having the maximum amount of rounds in then (25 for the RAK and 15 for the CR75) even when I dragged them into my backpack. It was only when I emptied the magazines that the real number was shown.

In todays exp test this issue seems to be resolved for me.

Dont know if this is useful, but I have the same problem and I figured I could capture some video from a daytime server. Somehow the effect isnt as noticable in the video as when I`m playing.
This is from the november 2 exp server crash test. Included are dxdiag and screenshot of video settings.