Just noticed that when it had unread replies, the unread reply count on the Postgres 12 announcement topic was at 303 (blue circle with 303). Upon opening the topic the latest reply the count changed to 1.
The topic is set to auto delete replies older than 5 days, there’s currently only one reply on that topic.
Looks like the reply count on auto pruning topics with unread posts isn’t calculated correctly?
This was on mobile, I didn’t think to check desktop before opening the topic and marking it read.