Tone changes on Xpand!2 instruments

[Elbergo]

Noob here. I'm mixing midi files and using Xpand! 2 instruments. It's the two guitar tracks that are troubling me. (I'll be speaking in terms of actual pitch here, not notes as written.) The tone is pretty much uniform from the bottom of the instrument range up to the F just below middle C. Then, at the F# just below middle C the timbre gets muddy and stays that way until middle C. At middle C the timbre brightens up (goes back to "normal") for the remainder of the range.

I'm using the Medium Hard Nylon Guitar patch for two tracks. When I switched to the Soft Steel String Guitar patch the timbre shifts take place on the same notes. When I compare my EQ with the factory default setting the timbre shifts remain the same.

I don't think these shifts are an attempt to mimic the change in tone when moving from wound strings to plain strings. If that were the case, the patch would not shift back to a brighter timbre.

So, is this normal for Xpand! 2 guitar patches? Normal for all Xpand! 2 instruments? Is there a way to fix or adjust the tone only for those few notes? It's frustrating - those notes get lost in the midst of the brighter notes above and below.

I don't know if these are related problems, but when I set levels in the midi studio they don't get saved. And sometimes when I open First the playback is weak and extremely distorted.