There’s been some discussion about the dead instance checker over on !fediverse!fediverse@lemmy.world being a bit overzealous but I didn’t see anything here, so I wanted to raise it.
I did some spot checking of the instance table and can confirm that several of the instances with an older updated date were indeed actually up.
I’d have to go digging on github but I thought there were going to be periodic checks of the dead hosts in case they came back. Maybe someone else knows?