this is something thats been there for years, it usually tends to happen more often if the boss is aggro'd before they all jump down (one of the 4 bosses becomes targetable before they jump down, which i you have range can target it and make weird things happen)
i have my main house (grand topal hideaway) listed in the housing tours, it has multiple target dummies, scribing altar, and grandmaster stations (in progress being filled out), as well as almost every antiquity furnishing on display to preview them