Riot-web is notifying me that there are unread messages in a room. There are not. I can make the notification disappear by clicking around in the timeline section of the room (possibly), but then if I navigate away from the room (or some time later), the notification keeps coming back.
For the web app:

I can confirm this on Linux client (i have 4 Linux computers and all of them exhibit this issue).
I have a synapse home server and even if i have very low traffic, i get ghost notifications. It seems to me it is mostly from users, not rooms.
I think this is the issue I'm experiencing - the unread line in the chat log itself disappears when you read something, but otherwise the unread status does not get removed. The read status doesn't get propagated to the other room members either until I send a message or open the room in the mobile app.
Having the same issue I think with #riotweb-translations:matrix.org All the time :/ Sometimes needs half an hour or more to clear on all devices. It gets worse when someone redacts a message atleast on my side.
it seems that I face ghost notifications myself and these are god-mode-zombies like which seems impossible to obliterate: restarting app, rebooting system does not make them go away at all. They do stay like this forever (more than two week by now). My tray icon used to display 2 unread such notifications for weeks and now it got to 3.
Since a few update cycles ago, mine forever remains at 1 unread notification on the app badge on every platform, but there is no room or user for which the unread is indicated on, when I open all the apps.
This still occurs on at least riot-web and riot-android (https://github.com/vector-im/riot-android/issues/2969). One of my rooms eventually gets marked as having 2.8K unread messages even though there has been no activity in it. Switching back and forth between rooms on the web client seems to reset it. On android it seems to clear if I send a message to the room.
Can confirm, this still happens. It happened concurrently to the last message in a room being removed which may or may not be related.
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Can confirm, this still happens. It happened concurrently to the last message in a room being removed which may or may not be related.