4u2ges (8/27/2022)
It gives you a clue in the error. Did you rename a mesh after the import?
CC adds underscores to the mesh name for spaces, but you should not rename it before blend shapes import.
Mesh name is also case sensitive. Changing one letter case for the mesh name would invalidate consecutive blend shapes import.
I didn't change anything on the initial imports, I have over 100+ models with blendshapes, it's the same for all that I've tried so far.
I have no problem with them showing up in Unity if you look at the images.
This isn't rocket science, Unity detects it & even has nobs to drag to create blendshapes, where is this in CC4?
The naming is a standard viseme expression scale kit everyone uses for iPhone tracking.