Scenes empty in UI Editor

I have an issue where my scenes that I’ve previously set up are now showing as empty in the Settings UI. They are still defined in scenes.yaml, but none of the configured devices or entities show up in the UI when I choose to edit a scene.
The scenes run when an automation activates them, or I activate them manually.
scenes.yaml is included in my configuration.yaml.

Been like this for 3 days now, and I have restarted HA several times. There are no obvious errors relating to this issue in the System Log.

(It is such a PAIN that when you go to edit a scene it automatically activates! This needs to be stopped! Activating the scene should be a manual choice the admin deliberately makes. And trying to edit the scene is not a choice to activate it)

Here is an example:

Does anyone have suggestions on how to get my scenes reappearing properly in the UI editor?

lThe entire entities section seems missing (not just the entities themselves). Have you tried flushing the front end cache?

Do you mean on my browser?

This happens in three different browsers across three diff computers, and the mobile app on iPhone.

In the ios companion apps this is in the settings for the companion, in the debugging section.

It is weird that the heading isn’t even there, is 't it:

This is mine:

Can anyone else offer any help?
This looks like a significant failure in something server-side, and it make me worry what’s gone wrong, and what the long-term effect might be.

Thanks,
G.