Whoops, forgot to check this earlier. Sorry
@ivan the neandertal
Just tried it now on my Wins 10 device (Browser: Edge) and couldn't reproduce the problem. When there was a flashing message it was a new message.
I'll swap over to my other computer shortly and check there. What browser and operating system are you experiencing this on?
Which area do you have messages when this occurs?
Pretty sure even on mobile it won't stop flashing until an announcement message is read, but this could be a separate thing depending on how it's behaving