I just had this issue today and found that the vertex colors import correctly into Godot from Blender when I plug the desired color attribute into the material somewhere before hopping over to godot. I’m not sure why it works this way, but that’s the least tedious solution I could find.
In my case though I have the .blend files set up in my project directory and the blender path defined for direct importing rather than using Glb or Gltf: here
Using Godot 4.5 stable and Blender 4.5.3LTS.