When Montage/MODX is in multi-channel mode, the assignable knobs (set to [ASSIGN] mode) change from Sysex (no Part selected meaning Common is selected) to CC (one Part selected). This was a design choice by Yamaha to make each level have a different standard message for the knobs.

The thought is that you would use either Super Knob to modulate the COMMON assignable knobs or use a Part level assignable knob assignable knobs. Both of these options use the easier-to-use CCs to modulate the Part assignable knobs or Super Knob.

These same knobs have 3 or so other modes of operation (not acting as assignable knobs - but "fixed function" knobs). And also these fixed function knobs have different modes: common or Part.

There are LEDs on your MODX indicating the mode the instrument is in - but you can also use the home screen as I think you are today looking at the white box around a Part or the Performance (aka Common) name.

When Montage/MODX is in single-channel or hybrid mode, less of the "internals" are transmitted so you should only see the CC messages for assignable knobs.

If you want CC messages - press the [PERFORMANCE] (HOME) button first. Whenever you recall a Performance from Live Set or Category Search - the Performance will not have any Part selected. Then press any Part so the Assignable Knobs will transmit CC in Multi-Channel MIDI mode.

Personally, I never touch a Performance at a gig. I only recall Performances using Live Set and don't touch the screen or anything that would select an individual Part. That's just me. I program Scene buttons to turn on/off keyboard control, volumes, arpeggios, etc. This also means that my assignable knobs are set to COMMON and would transmit Sysex. Additional fiddling to select a Part would be necessary to have the knobs transmit CC. Before you [STORE] (save) the Performance to the User Bank, set the [ASSIGN] button or other button(s) for the Knobs to match the mode you want.

And ...

If you always want your knobs to transmit CC values - there's a DAW Remote mode for that. Where you can set the Knobs, Sliders, etc. to transmit any CC values you define. I would use the plugin control mode for this. There are a few different DAW Remote modes that have a slightly different focus to meet different goals.

This may suit your needs better.

Bill,

You're right - I didn't have my instrument plugged in and flipped the logic. Editing my response for correctness.

COMMON are Sysex, Part Level are CC.

Another user's summary:
https://www.yamahasynth.com/forum/knob-slider-midi-chart-v2-0

BTW: MIDI-OX is my go-to monitor for the PC too.