[@let-me-see Participant 10 years, 8 months ago]

Oh, okay, now it gets even worse: I ran this repair option: “Recalculate last activity in each topic and forum” – and afterwards, the last correct entry under “Freshness” in the forums main page finally became an older one, too. Seems like now they are all the original thread starting entries. The exact opposite of what this repair option should have done. I ran this option multiple times tonight. No wonder the Freshness got more and more broken.

So, maybe not a multisite issue after all.