Are you absolutely sure? I just updated to the latest 2.4.3+ to test this and my teacher in a course with editing on, when he goes to the front page he doesn't see the edit icons or have ability to edit the front page- which is how it should be. I wonder either - do your teachers have site wide privileges or is there an issue with global privileges with your LDAP set up?
D'oh, hanging my head in shame..... My account (non admin) was in a custom role that somehow slips into having publish rights on the front page if navigated via the means I explained above. Sorry my bad!!!! Nothing to see here