Since there is zero taxable income in box 2a, there will be absolutely not change to 2019. You can amend if your want just so the IRS gets your reason for amending (to add a 1099-R) that does nothing. I would take the trouble of amending. It the IRS ever questions it (which id doubtful) then a phone call should clear it up.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
