Flight viewable on website but missing from /schedules

Hello, I am trying to find the following flight but do not see it being returned from the /schedules api, is there a reason it is not being returned? thank you

Flight: XE475 (JSX475) JSX Flight Tracking and History - FlightAware

I called the endpoint (/schedules) with the following parameters and got no results:
startDate: 2023-10-12
endDate: 2023-10-22
airline: JSX
destination: KPHX
origin: KBJC

No results. If I remove the origin then other JSX flights into Phoenix show up, but noticeably none from KBJC, including the previous flight that is viewable on XE475 (JSX475) JSX Flight Tracking and History - FlightAware from 10/15