Hi Jay,
There is nothing wrong, we’ll explain...
If you think of VOICE mode sounds as individual musicians, then think of SONG mode as a band of musicians in the studio. MIXING mode is literally, the (16) individual Voices plugged into the studio’s mixer. When you change from Voice mode to being one Part plugged into a mixer along side 15 others, some of the parameters of the mixer are inherited... think of the studio mixer channel as parameters that are applied to the instrument. The Channels on this mixer include both traditional mixer parameters and synth Part parameters. For example, all 16 channels of the mixer start with Volume = 100, Pan = Center, Reverb Send = 12, Chorus Send = 0, EQ = Flat, etc., etc. etc., these can be quite different from the conditions of the same Voice back in VOICE mode... Parameters of the Song Mixer include more than you’d find on an actual mixer... they include synth parameter settings as well, this also includes resetting all PB Range to -2/+2... similar to how a Reset command would “zero” a synth, it zeroes the mixer, all the channels return to a neutral state.

Because not all parameter settings are not brought along from Voice mode, you inherit some parameters from the studio’s mixer channel. What you can do is have the the MOXF *copy* those parameters which are not automatically brought along with the Voice when you place it in a Part of a MIXING. This is explained, step-by-step in this article:
Parameter with Voice: MOXF

If you have additional questions, post back here.

Yamaha's are a very deep keyboard. A lot of hidden parameters that go unnoticed. I've never dealt with mixer settings on a sequencer that didnt use all the voice settings. But, if that's the way this keyboard works.....then i will learn it.

i've transferred nearly 700 songs into this keyboard. it has taken months. guess i'm going to tweak a few more settings before this keyboard is gig worthy

Yes, here on Yamaha synthesizers, the same Voice can be used differently in each Song or Pattern setup. So if you use that same Voice in another composition you are not forced to always use it with -12/+12 Pitch Bend. The Part parameters allow you to create a unique situation for each composition... without destructively changing the original Voice. At first, it may seem strange or different but once you realize you can customize the same Voice differently for each instance you use it without necessarily having to create a new Voice.