No 404 on existing folders

Does this show up for both URLs? In theory, it should, which would mean that both URLs are going through show_404(), I just don't understand why one would have a different result from the other.

Both give a 404 error according to the logs, but one 1 (the one with the index.php) does show a correct 404 error and the one without the index.php shows weird symbols.

That's the reason I asked here, I really dont get it anymore :/