Caused by rBa6a9a12e8f32: Fix T75142: No autokeying with pose mode X-Mirror
Other relevant commits:
rBb8ca806b7798e2f8dd6effca8f0d081b3cd8c23f
rBde530a95dc7b482dc22c933b9b8b2a98c79b5663
The issue is caused by some leftover BONE_TRANSFORM_MIRROR flags on a bone from previous runs (file in the report had the flag still on forearm.R).
With these false leftover flags still set, pose_grab_with_ik() cannot work correctly.
Culprit commit above removed the early clearing of this flag on all bones, this should be restored [this happened in`count_set_pose_transflags()`].
This should only be done in the beginning of the transform process, so now still clear the flags early in 'createTransPose()' [but dont restore this in 'count_set_pose_transflags()' -- this will be called from special_aftertrans_update again, so placing the clearance here only complicates things (autokeyframe_pose() still needs to work as well)...]