I think the stream for Fox KCPQ Seattle has changed. On fox.com logging in with my Hulu credentials currently playing is MLB baseball, but if I open Fox in channels on my FireTV, I get a never ending stream of "Stream FOX primetime and live sporting events on FOX NOW, FOX SPORTS, FOX.com, and FOXSPORTS.com". I did try an update to the latest pre release, currently running 2022.08.27.2357.
EDIT: A newer version seems to have fixed this