Here's several bugs I've come across in the past month or two:
The RAF roundel is duplicated on these damaged Spitfires:
The propeller blades of the Spit 16 are not visible when viewed from the outside through the canopy:
When oil leak marks on this Hellcat cover up the propeller blades, despite the blades being in front of the cowling:
This gun turret (I think it was a 40mm on a destroyer) appear to be floating in mid-air (when viewed from some other angles, the gun mounts appear as normal):