Hmm maybe that wasn’t the one I was thinking of. Someone put a weird topic in Discourse Hub recently, I recategorized it, and I thought that might have been the one as it is suitably weird.
Sorry, could not view edits on ie11 touch cc: @zogstrip so I wasn’t able to verify.
I’m not aware of any other reasons new topics would not be marked new, other than being in a muted category. Hasn’t ever been reported on any Discourse instance I’ve ever seen, either. And of course I have entered virtually every topic here created all time, and I can’t ever recall seeing a topic that I wasn’t aware of originally at the time of creation due to being marked new.
“New when not yet viewed” is a straightforward check; did you enter the topic yet or not? Possible it is buggy, I guess, but nobody has ever reported that, either.
It’s also possible there was a weird edit collision if the OP edited at the same time as me during the grace period maybe? I distinctly remember a bizarre topic in Discourse Hub recently and I know I recategorized it. That would absolutely have caused you not to see it, but you’d also know if that was the case since the notifications control at the bottom of the topic would say “muted due to category blah blah”.
Meh, tested on try, all seems OK. Not sure, but I guarantee you that topics that start out in a muted category and are recategorized somewhere else will still be muted for you.