Hi Lee,
There are 3 different split points: Style, Left and Right3.
By default, the Style and Left split points are set to the same note (e.g. F#2) and the Right3 split point exactly one semitone higher (in this example G2). Then the Style control and the Left area go up to F#2, and from G2 the Right1/2/3 parts can be played layered.
If the Right3 split point is set higher, the Right 3 part can only be played from this higher note. In your case, the Right3 split point is probably set only slightly higher (e.g. to G#2 instead of G2). Then the Right1 and Right2 parts will only sound on a single note (namely G2) when the Right3 part is activated, and only Right3 will sound above.
Please refer also to the section "Setting the Split Point" in the Genos Owner's Manual, pages 49/50.
Hope this helps!
Best regards,
Chris