There are 2 glitches I've encountered with grotesque guardians ( these are rather uncommon).
1st: during last phase of the guardians you are teleported into a box. Usually the box has 1 exit in which u can avoid being hit 60, other times there are no exits and ur forced to get hit a 60.
2nd: during the orb phase, sometimes u cant press on the orbs to negate the healing. Additionally, sometimes the orbs dont even heal the boss and just stay there on the ground forever. at some point I had 9+ orbs on the floor and couldnt pick up the "real 3" orbs the boss continued to drop.
Would love to have these fixed. Hope my explanation was clear, if not let me know and il try my best to elaborate.