Federal tax on taxable income at line 21 on Schedule 11 is doubled in a scenario where all of the below applies:
1. Taxation year ends in 2016
2. Taxable income is greater than $200,000
3. The return is a testamentary trust type 903 or a grandfathered inter vivos trust.
Workaround: Override the amount at line 21 with the amount from line 8.