If you’re encountering issues with scripts not displaying correctly in your system, consider removing the most recently added scripts, especially those that aren’t functioning as expected. Scripts could be partially downloaded due to various reasons, leading to this kind of issue.
I have also checked in Virtualmin -> System Settings -> Script Installers -> Disable Scripts and WordPress, WHMCS, SquirrelMail are ticked but Roundcube and phpMyAdmin are not ticked
“can be used to de-select scripts” implies ticking a checkbox on that page “de-selects” it ie disables it.
Anyway ticking the phpMyAdmin did nothing to change this problem.
Also note Roundcube was available to install and its box on this page was also not ticked.