Alaska Air 834: 737-900 or 787

Running Planeplotter and Dump1090 from Lincoln City, Oregon this evening with little visible traffic due to poor location.
I was tracking N442AS, ICAO A5521C as flight 834. listed it as a 2013 737-990ER/W belonging to Alaska Air ASA. FlightAware showed ASA 834 consistent with PP.
However, looking up N442AS on FA brings up a 878 last seen in June, also owned by ASA. Looking at FA’s underlying registration data shows the 739.
Am I missing something along the way?

The FA track I checked was