The "due date" for the 2018 excess was April 15, 2019. After that you will owe the 2018 penalty on your 2018 tax return.
The due date for the 2019 tax return is immaterial. ANY date is *after* the due date of the year that the excess was for, which was 2018 and that was due date was April 15, 2019. If not withdrawn by the end 2019 then you also owe another 6% penalty for the 2018 excess still in the account.
As I said above, the "due date" ONLY applies to the tax year that the excess was *for*. In subsequent years ithe last day to remove without another penalty for that year is Dec 31 of that tax year.
**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.**
