phtcloud Thank you for clarifying. I've checked, and this issue seems to be different from the one discussed in the thread you linked. The issue in that thread concerns rotation animation, whereas in this case, the rotation changes occur at the setup pose stage. Based on my observations, the problem appears to be related to the order in which constraints are applied.
It also seems likely that there was a bug in version 4.1, and that the fix in 4.3-beta altered the orientation as a result. I’ll email you a simplified version of the skeleton you sent so you can take a closer look.
In the original skeleton, the transform constraints on the parent bone are applied after those on the child bone. Generally, modifying the parent after the child is not desirable. If you open the project in Spine 4.1, select the Constraints node in the tree view, and press the Reset button, the order will change so that the parent bone’s constraints are applied first. This, however, will rotate top_jt12 and top_jt13 by 90 degrees. I believe this situation likely arose because the parent bone was modified later, so the rotation observed is actually the correct outcome.
Unfortunately, you’ll need to address this yourself, since it results from assuming a buggy state as correct.
