I have a pretty simple site whose page hierarchy looks a bit like this:
However, on the website itself, each top-level entry shows the second-level entries from all top-level entries, not just its own. So when I click on "B", I see all second-level entries from A1 to C3.
I really have no clue how this happened; I've never had this problem with Silverstripe. It doesn't seem to be theme-dependent; resetting to the original "simple" theme does not fix the problem. Flushing does not help. /dev/build does nothing. Is there something wrong with the database? I don't know, and I don't know what to do to test this idea, or fix the problem if it's true.
The Admin tools show the hierarchy just fine; it's only in the frontend where things are wrong.
I really have no idea where to even start to fix this problem. Any help?