Well my T2 transformers would beg to differ...
I've never had imbalance issues with the 100 or so Alpha pots I've used but this could be one of the broken ones. A few of the pots I got in my first shipment had some sections reversed so they wouldn't work correctly. If you can feel a notch when turning it then it would be one of these. I thought I had found them all and returned them to Alpha but I could have missed one.
Regardless, just PM me your address and I'll send you a new pot. We can't have an imbalanced amp.