Unrecognized UID on editor start for files such as default_bus_layout and main_scene #117362

Tested versions

v4.6.1.stable.official [14d1969]

System information

Ubuntu

Issue description

I am observing this error anytime I load my project in the editor:

  ERROR: Unrecognized UID: "uid://bowdqq181dypn".
  ERROR: Can't save resource to empty path. Provide non-empty path or a Resource with non-empty resource_path 

in this case, uid://bowdqq181dypn is the default bus layout.
the only place where it is referenced is the project.godot:

[audio]

buses/default_bus_layout="uid://bowdqq181dypn"

when we replace this project setting with a traditional res:// path, it no longer complains about the bus layout, however, we then instead get an error about the UID of our main_scene being unrecognizable.

in conclusion, it appears to affect any files that are loaded early (when project.godot is read) via UID.

Steps to reproduce

unfortunately, I have not been able to reproduce this issue in a fresh project.

since this appears to be a load order issue, it presumably only occurs when the editor has to take more time loading resources on startup, and so something happens "out of sync".

perhaps something about the UID cache not having finished loading when the project.godot is read?

Minimal reproduction project (MRP)

see above