returned to a project and 3d mesh is distorted

Hey,
I returned to a project and my character 3d mesh is distorted.

How it should be:

I dont know where to begin debuging this, or how it could have been caused.

I have tried Reimport on the GLB but it didnt work.
I can drag+drop this GLB into a new 3d scene and it appears (in the T pose) as expected.

Any pointers, or even steps to try and debug would be appreciated.

Cheers