Steps to reproduce

1. Make sure that your Moodle files directory is writeable by the web server.
2. Log in as admin.
3. Go to Site administration > Plugins > Install plugins.
4. Either via uploading a ZIP (link), or via browsing the plugins directory, attempt to install the "enrol_xp" plugin
5. During the installation wizard, you will reach the Plugins check page, where you are notified about missing dependency - another plugin "Level up! - Gamification" (block_xp) must be also installed.
6. Ignore the warning, do not install the missing dependency and go to the next step by clicking the button "Upgrade Moodle database now"
7. You end up on the "Plugin dependencies check" page with the information "Dependencies check failed for enrol_xp" displayed.

Expected behaviour

Clicking the "Continue" button should take you back to the previous screen where you can either install the missing dependency, or cancel the new plugin installation.

Actual buggy behaviour

You are stuck on the page, "Continue" just reloads it and there is no obvious way to get out of it.

Workaround

Don't panice. Once you are on this dead-end page, just replace the URL in the browser with your Moodle server's URL and the install wizard will start from the start. But it should be more intuitive.