Some of the workarounds aren't workarounds for production, some of this is unacceptable.
From the release notes: Maya
"If you want to add your HumanIK Control rig to an animation layer, it must be keyed in Euler rotation interpolation mode. Before keying your rig, set New HIK curve default to Independent Euler‐angle curves or Synchronized Euler‐angle curves in the Animation Preferences (Window > Settings/Preferences > Preferences). (ENCS‐1507, Suites)"
There are more but this one was a big one.
Mobu: release notes ( I am posting a few that I think stand out
- Loading character animation with layer animation can corrupt control rig animation.
Workaround: Merge layers. (ha! not a workaround, fail)
- Creating new animation layer resets non-keyed modifications to object and control rig poses.
Workaround: Create new layer before posing character or store the pose through the pose
controls before creating the layer.
- Problem with Parent Child constraint when Rotation Y = 180.
Workaround: Replace parent child constraint with position and rotation constraints.
- Exported clip from Story imports with changed clip length.
- EVERY TIME THE MOTION FILE IMPORT GETS BROKEN AHHHHHH- Translation on the root Joint of ASF Skeleton not retained when importing AMC motion file. ( look out WETA and Giant houses)
Based on the bugs and limitations for the HIK solver if you are using MotionBuilder use the MotionBuilder solver and delete the HIK solver from the scene. Don't use the HIK solver settings in MotionBuilder and expect it to work for editing.