There is a forum topic called Cruises which apparently has no content, or at least I can't access it.
Topic with no content
The thread in question for Peter to have a look at: https://www.travellerspoint.com/forum.cfm?thread=124882
Something probably went wrong with deleting its one and only post (which was almost certainly spam), leaving the empty thread container behind. That should automatically be deleted as well when it no longer has any posts, but sometimes there's a bug which causes? that process to not finish.
Yeah, a weird bug. The thread should have been removed as Sander says.