I’m not sure if I’ve already made this point, but I suspect that it isn’t TfL making the schedule on/off decisions, but is a function of the contracted bus garage.
(TfL provides the cash to run the bus services under contract, but you can see the contracts online here - search here - Bus tender search - Transport for London and example route 603 is here Bus tender results - Transport for London )
Anyway, it’s is totally possible that the Journey Planner knows only about “never” school bus dates, and shows the services on all “possible” other dates.
Or, there’s a secret list and someone needs to FoI it?
