MT3000 Beryl AX 4.7 beta wireguard config edit

I can open a wireguard configuration for editing but the apply button does not save the edits.

In this case I was attempting to change the endpoint port number

Check this configuration in the SSH after you change the config and click the 'Apply' button:

cat /etc/config/wireguard

Is the config displayed in WebUI same as the SSH configuration?

No.

In the GUI the edit window has a red-lined boarder and the Apply button shows a shade change when selected.

As the perms are 0775 and owned by root does the logged in user (admin?) have permission to write the edit?

Everything on the router runs as root, so that should not be a problem.

It seems that the UI check there are some parameter missing.
What port did you change to?
You can post screenshot with your private data marked.

The configs I edited are machine generated and already working.

I tried various edits. Add a space into a line, change the DNS name for the server or a port.

None are saved.

I understand. But if you can give details it will help to solve.

Maybe the most pertinent is that these configurations apply to an added provider rather than any of the pre-configured public services.

The configuration was created by uploading a file.

If I edit the external source .conf and add a new configuration it works.