I was watching the thread below, and wandered off for a coffee.
While I was gone three messages along these lines appeared in my email Inbox:
They were at 9:59 am, 10:00 am, 10:04 am (my time, the times the emails arrived).
Now I was gone for around 10 minutes, and certainly didn't read those messages in that time. In fact according to the forum:
« Reply #24 on: Today at 09:04:19 AM »
« Reply #25 on: Today at 09:05:04 AM »
That's about 50 seconds apart. So the behaviour of:
... you won't receive any more notifications until you read the topic ...
is not working.