@Artur Maklyarevsky the only reason you're getting notifications is because you're watching boards, lists or cards. When you comment on a card, Trello has a little checkbox to watch the card which is checked by default. If you uncheck it once anywhere, it will no longer be checked anywhere by default, so probably you commented on some cards on the public board and now you're watching them. All you need to do is go in an unwatch the cards when you receive notifications on them.
lian thanks for the quick reply.
here is the thing.. i took a deep look and found that im not watching any boards, lists or cards.
what trello’s UX team should simply add is an option to STOP ALL NOTIFICATIONs. most of the app world does this. this just feels like a nasty dark pattern or bug at this point.
I don't get an X to remove an unwanted board in the recent list. However, I've discovered that it's set with a cookie in my browser as the unwanted board doesn't show up anywhere else or in incognito mode. I haven't found the right cookie yet. Apparently it's not under "trello". It could also be browser storage and not a cookie.
OK, so after much digging I found it! It's in local storage. Go to developer tools > Application > Storage > Local Storage > https://trello.com > recentBoardsState-[string-of-hex-digits]. The list of ids shown is in display order. You can right-click on the value and (carefully!) edit it.