After opening the homepage (fe. after a login to phpMyAdmin), an AJAX request, fe. clicking in the navigation tree to expand a database, is not executed until the current version is retrieved.
If getting the current version data takes some time, the AJAX request is seriously delayed. After the current version information is added, or retrieving it has timed out, all AJAX requests run smoothly from them on.
Diff:
Fixed with https://github.com/phpmyadmin/phpmyadmin/commit/2f978adba9ca345064f38844dabb484d33a933c3