Steps to reproduce the issue

enable the Redirect plugin in Joomla 4.

Visit example.com/hahahhaha (note its a 404 error, this is correct)

refresh the list of links in the admin console for the Redirects /administrator/index.php?option=com_redirect

see hahahhaha in the list

Click the (X) next to it

Expected result

Validation Error! There is no "New Url" and so its invalid to be able to publish this link as proved if you try to edit the link by clicking hahahhaha and then clicking save, you get a validation error

Actual result

The link is published, bypassing validation rules, and creating a data integrity issue.

System information (as much as possible)

(bug might exist in Joomla 3 - not tested)

Additional comments