Oh no wait… that’s me.
As far back as Wednesday last week when I was working my way through this problem I joked about the artist being stupid. This was a sort of anti-joke because I get annoyed when a programmer doesn’t take responsibility for a bug and they multiple re-assign occurs. So much so I’ve developed a blind spot to compensate and assume the artist work is correct.
In my defence it turns out many importers and viewers actually have hacks and fixes in for common artist error. So the hand model looked FINE in the official viewer.
Turns out I had rigged it wrong and as a result the bind poses couldn’t be calculated correctly.
Solution: Re-rig and animate the model
On a side note I’ve lost easily 20+ hours on this single issue.