I have strange "problem": for appr. two weeks now whenever i open forum i get one unread topic more than it's real. If i read all subscribed topics it shows zero, but when i close forum and reopen it i get one unread again. When i click on "unread" page says "nothing left...impressive" and title jumps to zero unread.
It's the same on all devices (tablet, phone, pc's) and cache clear doesn't help, if i sign off and sign in again also doesn't help.
Where are "unread" stored anyway? What to do?
I too have the same issue.
Yep same here, very annoying.
That's to keep you reading... 
Yeah - I originally thought it was my browser cache - but no. Then maybe a real unread message would reset it - didn't happen either.
There's a Github repository to report issues on the documentation page but unfortunately nowhere to report forum bugs.
Same problem here since some days.
Seems to be related to the Discourse forum software:
If I understand correctly, the HA forum admins need to take action.
@petro Can you please take a look?