Check yesterday's planefag reports. That is the wrong plane it is this funky little fella Pipistrel Pantera.
Plane is on a US-wide sales and certification tour.
Moar info here -
https://www.pipistrel-usa.com/newsletter-133-september-2020/
https://www.flyingmag.com/story/training/pipistrel-four-seat-panthera-first-us-flight/
Not the same type. >>11923493 shows what appears to be a Rockwell Commander that was deregistered in 2014.
Probably some sort of error, don't know for sure. Civ air does sometimes pop up on MLAT. My best guess is it might be due to a temporary certificate being issued.
Oddness does occur like the phantom island lat/long 0N/0W & the random Spanish planes that pop up in southern California.
Oshkosh is home for the EAA - Experimental Aircraft Association a light plane mecca. Ties in with the sales tour.
Looks like avoiding that lump of weather to the left of his track. prolly flying in from Iceland/Europe.