I just tried https://p.programming.dev/profile/settingsand it's effectively the same. The save spinner continues indefinitely (no apparent timeout, unlike the other). A load of the page in a different tab shows no change.

Edit to add:

This time, however, there is a CORS error in the console. But it has a status of 504, so I'm thinking it may not be an actual CORS issue, but rather a backend timeout issue that's presenting via a CORS resource load.

With the attempts on the main interface, it's same domain so no CORS at play. Perhaps it's still a backend timeout issue but there's no error that gets passed up.