Description of the need In rich text editor in image details, users are allowed to click the insert or update button even if they do not have a file chosen.
Proposed solution You could block the "Update" button until an image is added or have a popup to notify the user that they do not have an image selected when clicking insert/update.
Additional information
Inserting an non-existent file:

Updating after a file is removed:

Recent comments
Backdrop CMS: 1.34.0 Installation profile: standard PHP version: 8.4.21 Drupal 7 compatibility: on Database server...
User seeing admin stuff
Sounds maybe like something is caching pages for all users when it should be caching per user -- just a wild first guess. (If this was so, she would have gotten an error if she tried to click on...
User seeing admin stuff
This appears to be the issue that was created, https://github.com/backdrop/backdrop-issues/issues/6401
format for image upload directory spec