QC35 - Annoying hissing/white noise in left earcup
I bought Bose QC35 last night only and was enjoying it. After using it for sometime, I upgraded the firmware from 1.0.6 to 1.2.10 via Android's BoseConnect app. It upgraded smoothly, but after the upgrade, after about 1 hour of usage, when I stopped the music, there is an annoying hissing sound emanating from the left earcup. Right earcup seems fine.
I know that ANC produces a LITTLE, negligible, hiss (which is acceptable and tolerable, and which didn't bother me, as I obviously tested the device in the showroom before buying it), but this annoying hissing is just too much to handle. It's like an assault on my left ear.
I was really frustrated and disappointed with Bose and wanted to get a refund immediately (it's not even been 24 hours!), but thought I would first post about it here before doing that and seek some help.
Please help me regarding this issue and what to do!