Open threads list (All threads)
Click some thread open, read few minutes
Hit Back button
If you're lucky, you see heading like 'There are XX new or updated threads, click here to load them'.
This is all good and nice, but actually new threads are already loaded.
Another case (maybe they are internally same):
Open threads list, wait for internal refresh to say 'There are XX new...'
Click on heading to reoload list
Click some thread open
Hit Back button
You sometimes see similar 'There are XX new...' heading - but new threads are already loaded.
It seems depend on browser - Edge behaves better than Opera (couldn't trigger second case), both are Chromium based.