The heading with {{int:sessionfailure}} does not render as a heading because it was a lost translation unit. Now it's impossible to restore as a proper heading.
Topic on Manual talk:Common errors and symptoms/Flow
It renders as a heading perfectly fine for me. Is this a problem with one of the languages? In that case which one?
There's supposed to be a third-level heading instead of the bare equals signs. This even happens in the original, English, version of the page.
Ohhh, I got very confused because this heading is duplicate (you can search for "Manual:How to debug/Login problems" and it appears twice)