Retirement tax questions

follow up: My 2018 1099-R Box 2a shows zero (0.00) box 4 is blank. Question: 1) Should I report and amend my 2017 return for this? turbotax software says I might need to amend my return (but I just got the form?) 2)Should I report this in my 2018 return? If the Answer is no for both when do I report this? Just confused on the process since I got the form in 2019 for a 2018 contribution related to an after tax money 2017 traditional IRA catch up contribution (hopefully this makes sense) Thank you!!