When I power up my SP4, Program Mode seems broken; the keys are transposed, the keyboard is split, various physical controllers do not work, etc.
The most likely cause for this is you have inadvertently edited or overwritten factory Setup #126 Internal Voices:
(In Setup Mode - Bank: User / Group: H / Sound Select: G)
Fortunately no harm done. Setup #126 though is "special" and should generally be left unedited.
Setup #126 (aka the Control Setup) governs what controller assignments, keyrange, transpositions etc apply globally to Program mode. In fact, you can think of Program mode as a special 1-zone Setup. Something has to define for Program mode what all the pedals, knobs, keys etc do. That is Setup 126's job. In altering it in any way, you tamper with the default behavior in Program mode.
For some advanced applications, one might purposefully edit Setup 126 to achieve certain global functions in Program mode. However for most users it should be left as-is. If accidentally altered, simply deleting it is the solution. Details below on how to Delete individual Objects can be learned about here.
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