that bug appears too on a fast gr of a streamer, shenron62.
every add were killed and also the boss but didnt appear un tchat and in geom didnt proc
that bug ain t on normal rift only on greater rift !!!
https://clips.twitch.tv/JoyousLuckyDelicataBuddhaBar-NTfMMQXK2vnAC2Jp
also named horror
https://clips.twitch.tv/ShyMoldyCaribouMrDestructoid-vqOpFS_369fLpLKc