BUG: Increasing foreign tax paid can suddenly decrease refund

Hi,

 

There seems to be a bug with how foreign tax paid (box 7) are processed in the Windows version of TurboTax Deluxe 2021. Here is an example:

  • Box 1a and 1b: 5000, Box 7: 0, refund: $609.
  • Box 1a and 1b: 5000, Box 6: 0, Box 7: 500, refund: $1109.
  • Box 1a and 1b: 5000, Box 6: 0, Box 7: 565, refund: $1174.
  • Box 1a and 1b: 5000, Box 6: 0, Box 7: 566, refund: $1175.
  • Box 1a and 1b: 5000, Box 6: 0, Box 7: 567, refund: $575.
  • Box 1a and 1b: 5000, Box 6: 0, Box 7: 600, refund: $575.

I would understand if the refund reached a plateau as the foreign tax paid increases, but this sudden decrease doesn't make sense. How can I open a bug with TurboTax?

 

Thanks.