Back door IRA help!

As a beginner, I made a mistake from the very beginning. And it tends to mess up my tax return for 2020. Need your experts' kind help here!

 

In 2019, I made 2* $6000 contribution to a traditional IRA by mistake on 12/24 and 12/26, respectively. After I realized it, I requested to withdraw the excess amount of contribution which was $6000. 

In 2020, Jan 2rd, the withdraw was successful. So I made 2020 traditional IRA contribution of $6000 and convert the total $12000 to a roth IRA. 

 

Then I got two 1099-R froms for 2020, one form has $6000 in box1, $0 in box 2a, unchecked in box2b, code P1 in box 7 and IRA/SEP/SIMPLE box checked. The other has $12000 in box1, $12000 in box 2a, checked in box2b, code 2 in box 7 and IRA/SEP/SIMPLE box checked. 

 

When I input the first 1099-R form, there is no tax penalty added, but when I input the second one, it adds up a few thousands which I know it is not correct. All the money I contributed to the traditional IRA is after-tax and I have never got any tax deduction from IRA, so why turbotax calculates so much extra tax for the second 1099-R?

 

I followed the step-by-step guidance from this thread: https://ttlc.intuit.com/community/entering-importing/help/how-do-i-enter-a-backdoor-roth-ira-convers..., but it just added up the tax. 

 

Please kindly help!!! Thanks very much!

 

(p.s. I'll never put myself to this hard situation, just doing the contribution/conversion for the same tax year.)