glTF files with Specular Glossiness materials are broken

Seems to be a problem both in Spoke and in spawning items inside Hub scenes.

I made a 3d model with textures using Paint 3D and exported it into a .glb file. It renders perfectly in SketchFab but if I choose the file from Spoke, it appears as a greyed out, non textured model.

If I use the SketchFab url in spoke, it gives me a JSON error, or a network error - it hasn't worked yet for me via that way. If I use the SketchFab url in a Hubs scene, same issue - greyed out untextured model spawns.

Any idea what might be causing this issue?

I'm on Windows 10, by the way.

Start by reproducing the issue in Spoke with the reported .glb asset, then compare it with the same asset loaded from a SketchFab URL and spawned in a Hub scene. Check whether Specular Glossiness textures are preserved during loading and rendering; done means the model is textured in both Spoke and Hub rather than appearing grey and untextured.

Written by the indexing model from the issue text.