After this week’s Hearthstone update, I can no longer see the only group I’m in in the social tab of BattleNet. I can still see chats with individuals. I uninstalled and reinstalled BattleNet, and also tried switching to using the Beta launcher just to double-check, but no luck. A live support chat couldn’t see anything wrong on your end, so he suggested I enter a bug report! (Also I’m on a Mac)