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