That’s exactly what happened, prompting an IRS CP2000 notice. I’ve actually got a 5498 for my SEP-IRA, labeled 2019, that shows both:
– in box 1, my 2019 TIRA contribution (which I made in early 2020)
– in box 4, a recharacterization of my 2018 Roth contribution (I did the Roth contribution and the recharacterization both in early 2019)
On line 7, the “SEP” box is checked. I’m not sure if that’s meant to refer to the line 1 contribution or the line 4 recharcterized contribution. I have persuaded brokerage to issue a corrected 5498, at least.