It's possible. The transition from "nice" to "nasty" was pretty sharp, so I'm actually suspecting I might have a bad driver. I never ran into this when playing my M2s loudly -- you could tell that they weren't happy because the dynamics would start to get compressed, so you knew to back off a bit, but in this case the speakers sounded fine... fine... fine... EWWWW... fine....

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8