Most ships have facings that don’t quite line up properly all the way through their full 360° rotation cycle. It looks like the same problem I had when I was first sorting out my own rotation setup, where it was essentially rendering 119 unique frames and making the last a copy of the first, but that doesn’t seem to be the case on your setup. Regardless, something in your Blender rotation setup needs fixed.
It’s most noticeable on the cardinal directions. The attached image was generated using TransData.exe /shipImages /rotation:270 /criteria:"s +extension:0xAc123099 to display the issue.
Thank you for the ticket, will investigate. I suspect its just a keyframe issue with the 3 keyframe rig. I have a few versions of the rig which aren't consistent with each other, so they need to be standardized as well.
Also of note: Since the engine supoorts PNG now, I can release a new rig that outputs transparent PNGs.