From time to time I go through the notifications, and click on the important ones e.g. replies, status changes, ... And then mark all as read. This works as expected. But when I go on Kagifeedback after a while (don't really know the time frame, on average I visit kagifeedback once every few weeks), most (if not all) of the already marked as read notifications, are marked unread. I know this for sure, as I already replied to some mentions which appear as unread.
I expect marked as read notifications to stay marked as read.
Don't know if this is maybe a client side sync issue, e.g. an old client side state gets merged into the server state or something like this, but 90% of the time, I visit Kagifeedback from mobile (same device/browser), so that is very unlikely.