Runtime exported glb file can be invalid (& bigger)

[andypoly]

Describe the bug
I tried importing a file at runtime and then exporting it to a glb file (SaveToFileAndDispose)
Online tests like https://github.khronos.org/glTF-Validator/ then showed it to be an invalid glb file (though can load)
Note also that the compression settings did not seem to change the size of the exported model and the exported model ended up bigger than the original (though I do not actually know the full compression settings of original).

ExportSettings settings = new();
settings.Format = GltfFormat.Binary;
settings.Compression = Compression.MeshOpt;

Files

before (file imported at runtime) and after (exported) files attached
beforeAfterFiles.zip

To Reproduce
runtime import and export? In time I could produce a project...

Expected behavior
A valid glb file is exported

Desktop (please complete the following information):

• glTFast version
  6.10
• Unity Editor version [e.g. 2021.2.1f1]
  2022.3.41
• Render Pipeline and version [e.g. Universal Render Pipeline 12.0]
  builtin
• Platform: [e.g. Editor, Windows Player, iOS]
  Editor (player)