Interesting, could be the Pres but it was operating with the callsign GRIMM99, rather than AF1 and it's not one of the standard presidential aircraft.
The particular 747 Flightradar tracked is one of those modified for use an airborne operations centre (hence the extra bumps for antenna)...
You do see those often travelling as part of the Presidential flying convoy..wonder if Pres snuck a ride on it or if his aircraft was elsewhere??