I realise this feature is only a couple of weeks old if you don’t count the preview to 5.8 we got leading up to the full release, but if anyone has any idea why this might be happening, I would greatly appreciate any help insight.
The facial solve is likely failing because the system can’t correctly detect or map the facial landmarks. Check your mesh topology, especially around the eyes and mouth, and make sure the face has clear, symmetrical features. Also verify your capture quality and try with a cleaner test mesh, as the auto-solve feature is still quite new and may have some limitations.
I did try another model similar to this one and there were no issues, so the problem appears to be confined to this model…(as if this character hasn’t caused me enough trouble)