Saving in the class editor sometimes shows a confirmation about unsaved changes

Steps to reproduce:

Unclear, currently not reliably reproducible.

1. Edit a page with the class editor
2. Perform a change
3. Click "Save & View".

Expected result:

The page is saved without further confirmation.

Actual result:

There is a confirmation alert, asking the user to confirm leaving the page with unsaved changes.

This also leads to failures in the integration tests in ObjectEditorIT in xwiki-platform-flamingo-skin-test-docker and in LiveDataIT in xwiki-platform-livedata-test-docker due to the alert.