52ec9379d6
Line 10393 defaulted program to 0 when subTrack.instrumentProgram was undefined (section clone with no instrument). _playNoteFluid receives program=0, calls program_change(ch,0) on FluidSynth, which picks program 0 from whatever SoundFont is loaded (MAIN session's SF). Fix: pass undefined -> _playNoteFluid takes oscillator fallback, no SoundFont loading.