That's correct, and that is an "issue" in the original pack as well. Fixing this is of course possible but would be quite time-consuming. I am grateful for such a high quality PC at a minimal price, and I think this is an issue that doesn't affect the overall result much.
I manage to get around and draw proper left and right sprites during the development of my own game SODHARA, I will contact ansimuz to add those to his collection if he agrees.