It’s just don't follow players, on normal difficulty its follow players normally, but on hard its simple don’t follow players. I'm not even sure that it’s a bug but are futures. This is not how you make hard content by changing already hard mechanic by lowering agro range of colors or demand literately back walking for colors to follow you, while you also reduce mini game time, so its don’t have enough time to back walk required color to correct pilar, is this means that you can only win dungeon by having luck with colors spawn ?

Also minions mobs that summon on phase 2 don’t have its normal charge phase, they straight up releasing power w/o ability to break protection.