Hi there, updating CSS changes in the Customizer can be very tricky as you can see on the screen recording. This happens even if the list is empty, with no custom CSS added.
This only happens when updating additional CSS, not other customizations in the customizer. If this is a theme issue or a general WP issue I don’t know?
The CSS updates eventually, but it takes several attempts.
that generally means that WP did not get a valid JSON response so it wouldn’t confirm the changes.
Some things to test:
1. Clear any browser caches and cookies. Or test in a private/incognito browser.
2. Disable ALL plugins temporarily and recheck to see if there is a conflict.