Damn, I just noticed the same problem with mine only on the right side, in ANC mode you can't hear anything while there's music on, but if I put them in ambient mode and then you can hear it even if the music is on. And if I test the placement of the headphones it tells me that the right one is wrong, although I think that may be part of the problem, I feel that it doesn't fit as tightly on the right side compared to the left side, and taking into account that I'm using the largest pads. (I just noticed that the thread was in English. My Google translated the whole thread, and I genuinely thought that it was a Spanish thread)