Could be. I tried burning them in for a while at very high volume. It did not fix the problem, and when I listened to piano music, there was a strange rattling in the left one, so maybe the drivers themselves were defective and not the wire. The right one was still fine after the brief burn-in even though it was at even higher volume because it is working properly. Interestingly, I couldn't hear the rattling in music without piano.
Did yours arrive this way or did it happen after a while? Mine arrived this way and luckily Amazon Japan agreed to refund me, though I still lose money with all the shipping and have to send it with DHL.
I was thinking of maybe getting the FXZ100s instead but I'm not sure I want to go through the hassle and risk again. If anyone wants to recommend something in that range that's available in the US, I'm all ears.