After you file

I would.  A "reasonable cause" is almost anything.

<a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/i8606.pdf">https://www.irs.gov/pub/irs-pdf/i8606.pdf</a>
"Penalty for Not Filing
If you are required to file Form 8606 to report a nondeductible contribution to a traditional IRA for 2018, but don’t do so, you must pay a $50 penalty, unless you can show reasonable cause.


**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.**