Currently 4 different mechanics share the same ground marker color, two which are instant death. The wall, the platform collapse, the 4/8 attack, and the small circle attacks. Light yellow with some red in it. The two remaining game mechanics are thankfully a bit darker.
It is really a hard differentiate between the instant death markers from the non-instance death. When the screen is filled with the 8 attack markers, you are supposed to see (with a rather short notice) a square shape among it. I have by now seen several times how people die when those two mix, not because they miss played but rather because they didn't see the instant death marker. I do not believe this is what the game developer intended when designing the encounter.
I am hoping that taco will fix this problem, but even better would be if this actually was changed in the game.