I recently installed the “new” version of phpmyadmin, and noticed that it didn’t work (in Chrome or Firefox, but did work in Safari). After a fair amount of troubleshooting, I found there’s a setting in config that is: $cfg['AllowThirdPartyFraming'] = true; (this overrides the default “false”) that seems to be for blocking iFrame attacks.
This caused the first part of the login page to load, but still missing the login fields, etc. After some more troubleshooting, this turned out to be Cloudflare’s Rocketloader. Which, you can disable either via path rule (just excluding everything with a given path), or by adding a value to the