Is there a setting to disable the IP blocking when a user is deleted?
Default behavior blocks the user’s IP when you delete them, but we’re behind Cloudflare, so this merely blocks a random IP in Cloudflare’s ranges, which later prevents some other user form accessing the site.
Using Cloudflare without the above template is completely unsupported.
Updated the title as this isn’t a user deletion problem, it’s a simple configuration issue which you can resolve by adding the Cloudflare template in your YML and rebuilding.