All our animators have mentioned issues when switching from IK to FK or vice versa. Often the wrists flip 90 degrees each time a switch is made. other times the arms change locations a bit, and sometimes the shoulders break and pop to new locations.
It appears to be an issue with the ART system, not the rigs themselves. Troubleshooting this has cost us plenty of time and is slowing down workflows.
We can’t find anything in the documentation about any of it. Have you seen this happening before or do you have any ideas?