I noticed that I occasionaly don't receive notifications of new posts for topics I'm subscribed to. The topic will show up with a star instead of a circle in the 'new content' list of topics, but in the top bar the bell icon doesn't show any new notification and the topic doesn't show up in the notification list either. Not sure under which conditions it fails.

Anyone else notice this?

I thought the star meant you had a reply in the thread. I seem to be getting notifications fine if I'm subscribed. I would imagine there is a limit on the number of subscriptions processed, to ease server loads. But that's just a wild hair guess.