Hi, I am not a Turbotax expert, but I am in the same predicament as you, and have been for years. What I do is go to the instructions for form 1116 on the IRS website. There you will find the worksheet for line 18. Using the instructions I calculate the correct amount for line 18. Then I go to forms in Turbotax and override the amount on line 18. I also override lines 19 and 21 because they don't seem to automatically change with the new amount on line 18. All of this should not be necessary. I don't understand why Turbotax can't calculate line 18 correctly. I hope this helps.
