The calculation in TurboTax is correct. The answer that you found to someone else's similar question, at the link below, explains why the excluded foreign income increases the tax on your non-excluded income. That is the way that the tax law requires the tax to be calculated. The new tax law has not changed this. The calculation is done on the Foreign Earned Income Tax Worksheet. Since you are using the CD/Download TurboTax software, you can see the worksheet in forms mode. You can also save your tax return as a PDF with all forms and worksheets, and the Foreign Earned Income Tax Worksheet will be included in the PDF.
https://ttlc.intuit.com/questions/4496461-when-i-enter-foreign-income-in-foreign-earned-income-it-in...
