It happened with many of them, most recently this one I believe:
Here's what I've observed:
- The bell icon is orange with counter [1]
- I open the notification tray
- I click the notification
- Icons become gray and count is now [0] (badge disappears)
- I am redirected to the discussion, but the notification keeps its gray background as if it wasn't read
- I click the notification again
- Now the background becomes white, and the notification count goes to [-1]
So it looks like I'm able to mark the notification as read two times.
I don't remember this behavior happening in beta7, so I guess something must be wrong. However I can't confirm whether it's a dev-master issue or something local to Discuss as there's an issue with my dev-master setup notifications and I can't get them to show up...
I'll need to wait on other notifications to see whether the background only disappears if there's no redirect when I click, or if it always disappears on second attempt.