I have no filters on and have gone through all my messages. My orange dot disappears and then constantly comes back when I move to the next message (both on Firefox & MAC app). I have reinstalled the MAC app and problem persists.
FWIW, Earlier today in one client’s org, I wasn’t able to get the orange Inbox dot to clear when it was supposed to, no matter what I tried. I just checked again and it’s clear now after not having done anything else.