Prevent Previous-button from leading from login screen to home screen

[adgerrits]

When entering zac.utrechtproeftuin.nl, a redirect to the login screen immediately follows. But because I noticed something of a screen beforehand, I noticed that after pressing the Previous button in the (Firefox) browser a few times, I get the (start) screen.
With every option you click there, you now redirect to the login screen, so no data leaks, but if authorization is not always checked, that could be the case.
The best thing would of course be if no start screen is shown before logging in.
ps: I don't have a login account and am accessing from the internet