Why is it asking for a detailed explanation for Form 1116 (COPY 1) Line 3b? I have foreign taxes on mutual fund inc only and this is being caused by a contrib to my HSA.

[sj_otherstuff]

I claimed a foreign tax credit on my original return. I am now amending my return because I made a contribution to my HSA in 2022 for 2021 but I made it after filing my return. Anyway, when I simply added the HSA contribution, which is a  Schedule 1 deduction (line 13), TT pushed me into a review where is wants me to enter a detailed description for Line 3b of Form 1116 (COPY 1).  I can't even see what changes were made to the Form 1116 so I'm not sure what is happening.

[RaifH]

It is asking what portion of your HSA contribution should be attributed to your foreign-sourced income. Most likely, this is 0. If you took those mutual fund dividends and contributed them to your HSA, then you can enter an amount up to your foreign dividends, which could reduce your foreign tax credit. 

For the detailed description, you can enter HSA contribution solely related to US income if you are entering 0 on Line 3b.