If you go to the 1116 Comp Wks, there's a box called Form 1116, Line 18 Adjustment Exception Smart Worksheet. Click on box B, "Total foreign source qualified dividends and capital gains from all copies of Form 1116 are NOT less than $20,000", and it reduces the value on Line 18, presumably following the Worksheet for Line 18 (although I don't know if it is precisely correct).
I have a similar problem that you had for Line 18 on Form 1116 AMT. I can't find a similar box to check to get it to be calculated by a modification of the instructions for Worksheet for Line 18, which I found in the instructions for Form 6251 (AMT).
