Strange. It seems lately I see that purple dot for the "Community" tab, with the "Forum Replies" section highlighted. Yet if I click on that, it says there have been no new replies. I check my subjects and it shows no new replies for my topics. What gives?

Solution: https://www.gog.com/forum/general/heres_how_to_remove_permanent_forum_reply_notification/page1

Forums are bugged, hope GOG can fix soon.

This has been a problem since at least 2016 or earlier.

Welcome to the party, powerhouse5000!

It's broken.

Sometimes, but not always, it helps if you first read the unread messages, and then click clear notifications under that bell icon.

I have no idea how the system works, but sometimes that has cleared the purple dot for few seconds, but sometimes for a few days actually.

This solution is not perfect, because not only it works very randomly, but you can't hit that clear notification button until you get some new notifications. To get them, you can try to add some games on your wishlist, and when there's a notification of a discount, you can hit it again.

So in short, we can all say "Go home, forum. You're drunk."