if you make changes to the Keyboard Octave setting and then change sequencer track, it resets to 0. I suppose this makes sense perhaps (as you might not want all your parts transposed by the same amount), it is a bit annoying given how easy it is to swap tracks.
Something weirder happening too? Yes - going from Pattern Play to Pattern Edit resets all the Octave settings - except transpose for some reason. To test:
In P.Play mode press alt + + or -
Change Octave settings to non-zero amounts - say Keys Octave -3, Mods Octave 2, Mempads Octave -2, Transpose 2
Press x
Press shift + one of the mod keys to select a pattern and enter pattern edit
Press alt + + or -
Settings now show: Keys Octave 0, Mods Octave 0, Mempads Octave 0, Transpose 2