Has anyone ever seen "GDScript_umusy"?

Had a bit of a crash and then the infernal error coming up xxx class hides a global script class.
On figuring this out and reloading, I notice in the script list that one of my gd files is now listed as:
card_image.tscn::GDScript_umusy
umusy

That file should be (and was) card_image.gd
It listed card.gd file as unsaved but I saved it back under its proper name.
I haven’t a clue what “umusy” is. I can’t find that file in my file system but it keeps coming back even when I close it.

I find it in the card_image.tscn file:
[sub_resource type="GDScript" id="GDScript_umusy"]
But when I change it to
[sub_resource type="GDScript" id="card_image.gd"]
It changes back to the former on running the project.

Trying to edit card_image.tscn in the editor crashes Godot.
The card_image.tscn file is definitely borked. Part of the script was inside the file.
Looks like I will have to rebuild it.

I managed to rebuild it and then trash the old card_image.tscn file and fix a bunch of dependencies.

Sometimes Godot gets hold of a thing and refuses to let it go.
I can’t really post this as an issue on Github since I am using 4.3 and cannot run anything newer on my system.

Thats a new one, maybe report the bug ?