This was my initial guess also, but does not appear to be the case. If that were so, the amount of rotation as well as translation would have been incorrect, since each of the two parent transforms apply a rotation.
I didn’t. I have more limited ability to follow the C++ code, and have never successfully set up a Slicer build environment (which would be needed to test a corrected solution, I think). I was hoping that a clear, reproducible example with the bug report would be enough for someone with these things already set up to take a look and hopefully see the problem and fix. I too suspect that the fix will be straightforward once identified.
I am looking forward to getting this working and trying it out for development and for problems such as these in the future. I can’t do it on my work computer because of sensible corporate security concerns, but I will be trying to get Claude with the slicer-skill set up on a home computer as soon as I can manage to get the time.