Hi Peter,
If the links are different, then check your permalink settings on the wordpress back-end dashboard ( Settings -> Permalinks menu ).
The second link simply looks as if the permalinks are not enabled, it is the default link structure for WordPress with the query arguments.
The cloudflare proxy issue might be a false positive flag for the cloudflare firewall or something similar. Maybe it sees part of the request similar to a threat or something like that and it automatically blocks it. Try checking the cloudflare settings, maybe you can adjust the firewall or add an exception for the back-end pages.