ISO sales are included in W2. I entered cost-basis to stop double-counting in wages, but they're still double-counted on AMT sheet. How do I prevent this? Is this a bug?

My company always includes ISO sales income on my W2. When I import eTrade, this gets double-counted. I can "zero out" the income from eTrade by entering the cost basis. However, this year, after zeroing it out, my taxes still went up by a lot. After digging in, this is due to AMT. On the AMT sheet, my "net alternative minimum taxable income" is my W2 income + my eTrade ISO sales income, so it's still double counting the ISO sales. How do I fix this, or is this a turbotax bug?