Misshapen Mesh FBX Export Here's the file.
Steps:

Select everything.
File ‣ Import/Export ‣ FBX (.fbx)
Turn on Selected Objects.
Export FBX
Upload character to Mixamo.


Expected:

Smooth surface
Uniform color

Results:

Areas around the mouth and neck are misshapen.
Head is grey. Body is white.

I'm worried that this might become a larger issue when I start to rig and animate this. How can this be fixed?
Turn on Face Orientation in the overlay dropdown and you'll see that the whole head and neck apart from the lips has the normals inverted.

In edit mode, select all and then ALT-N &gt; Recalculate Normals.