Boula, I love how thoroughly you’re going through this course! This honestly looks like a bug, I would expect that same thing that you expected. I’ll report it to the developers.
Edit: I’m not sure what could be done though, since the Z and Y axes are pointing in the direct opposite directions. Their average is zero, so those two are technically correct. And you can’t change the X axis without changing one of the other two. So it’s not wrong per se, but it’s not very useful.
