Using the internal Performance recorder will record everything assuming you turn recording on all tracks. Recording MIDI data with external devices is possible but becomes slightly more involved in setup. Then playback to Montage requires proper setup as well.

It's not flaky or inconsistent. It is insistent that setup is done "the right way" - which is counter to many other implementations out there. Therefore, past workflows do not work and introduces incompatibilities with other devices/controllers that do not match the requirements imposed on the MIDI configuration.

Sometimes you'll get bogged down in semantics. If your complaint is not technically accurate - sometimes support will dismiss what you have to say (right or wrong). Although I know what you mean - there isn't an issue with the MIDI protocol. The protocol layer is implemented fine. It's a layer above the protocol layer - the device specific implementation which is not dictated by MIDI spec - where Montage/MODX differs from its predecessors. Still, I know what you mean - hopefully this won't disqualify your feedback.

There is a way to get multi-PART instruments to work. But there may be some extra work involved to work around the consequences of current implementation.

I haven't, myself, written paragraphs of notes to document the ins and outs -- and that the "rules" list is lengthy enough to become difficult to manage is a fair complaint. My assumption right now is that PART 1 dictates what is sent out MIDI when you set multiple PARTs to the same MIDI channel (as both Hybrid and Single channel mode do). So if PART 1 limits by velocity or note range - maybe this is what you are seeing. I would, experimentally, make sure PART 1 has a PART with no limits on note range (C-2 to G8) or velocity range (1-127).

This opinion will probably receive pushback that it's not really that hard - and not to over-complicate things. However, it is true that there is an inherit level of items to manage and there are pitfalls if you do not respect (and know) the rules in place. I'm not sure I can over-complicate using a tool. Some tools require more steps, modes, "gotchas", etc. This isn't something I can adjust the complexity of (either upwards or downwards). It comes this way from the factory running the latest available software.

I see single-channel mode as something which can be a quick-fix for certain configurations, but wouldn't recommend its use when trying to document what the keyboard is doing.

The way I perceive this Hybrid mode to work is that I could theoretically layer up to eight parts, each with the keyboard control enabled, thus playing the layered performance on the Montage keyboard and capture the MIDI into whatever DAW I use.

That is not how it works.

Hybrid is a new MIDI I/O Mode setting, that allows you to Receive and Transmit on a single MIDI Channel from the linked KBD CTRL Parts, while the non-KBD CTRL Parts are still independently active.
When MIDI I/O Mode is Single, the MONTAGE can Receive and Transmit on a single MIDI Channel using the KBD CTRL Parts, the non-KBD CTRL Parts are inactive.
Only when MIDI I/O Mode is Multi, can the MONTAGE Receive and Transmit on multiple MIDI Channels using the KBD CTRL linked Parts. The non-KBD CTRL Parts are independently active.

When you select Single or Hybrid you are addressing the MONTAGE on a single channel and you are transmitting Out on that single selected channel when you are in communication with those linked KBD CTRL sounds. Only the notes you actually trigger go to the MIDI Out. The notes generated by the Arpeggiators are not Output. Think about it, only one channel of data... just the trigger notes are Output, when you play that single stream of MIDI notes back, you must reset, and re-arm the Arpeggiators... the MIDI data coming back to the MONTAGE MIDI In, are just the trigger notes (the actual notes you played).

If your Arp On/Off is set, the trigger notes coming back In via MIDI on that single channel will cause exactly what you heard when you originally recorded it... the Arps will be happening live. That’s the difference. Once you get it, it’s an “Aha” moment.

If it helps, take a look at the “MIDI Signal Flow” diagram on the “Settings” > “MIDI I/O” screen. Notice where the “Arpeggiator” block is when you select the various I/O modes. When in Single or Hybrid, the Arpeggiator is not in the path of signal going to the MIDI Out. The Keyboard goes straight to MIDI OUT. The arpeggiator is located just before the Tone Generator after the MIDI In.

Recommendation
First, you need to do is re-arm your Arpeggiators, (a quick Off-On of the Main [ARP ON/OFF] button ensures the Arp Phrases all reset to the top) then playback the single channel data you recorded with MIDI I/O Mode = Hybrid.
Prove to yourself that if you playback the same trigger notes to the same Arp setup... the Arpeggiators will do exactly the same thing they did when you originally trigger it. Including when you pressed the Arp Select buttons.

Then take a deep breath, and realize how the Hybrid MIDI INPUT/OUTPUT Mode actually works.

Hope that helps. If you are still having issues, post back.
There are other methods, (new methods) now of rendering Arp Phrase data to your DAW. Real-time transfers of Arpeggio data from synth to DAW is worth several credits toward a MIDI Jedi Knight Merit Badge.

The Arpeggiator filters out the notes you use to trigger the Arp Phrase, and only the recalled Arp Phrase goes Out via MIDI. Say it’s a drum Arp... well, data on one MIDI Channel cannot represent you playing across all keys and the drums banging away at C1, D1, F#1, A#1 etc., etc., — it’s fairly clear Arp data going out must have its own MIDI Channel. (and the only mode where each KBD CTRL Part has its own MIDI channel is MIDI I/O Mode = Multi). It is that simple and that complex.

Say it’s a guitar fingerpicking Arp... your trigger notes might well be the same notes the Arp Phrase is playing, except you are holding a Gminor7 as a whole note chord, the resulting Arp is a staccato series of eighth or sixteenth notes in the form of a guitar Arpeggio. With Single or Hybrid, it records your whole note chord. Play that whole note chord back to an armed Arpeggiator, it will do what it should.

Thank you both for your responses. To clarify, I am not talking about the Arp function at all. I am simply talking about playing the Montage keyboard directly, whether that's for a single part or a layered performance, with piano on part 1 and strings on part 2, both with the keyboard control enabled (green highlighted squares). Say I choose Hybrid MIDI and set it to Channel 1, both of those parts should sound while I play and every note I play on the Montage keybed should be transmitted to whatever DAW set up to record on MIDI channel 1. It simply does not work. It's every other note, at best, and typically every 4-8 notes. It makes zero sense to me. No arps are set to on. Even more confusing, if I choose, say part 3, which is not under keyboard control, I should then be able to effectively play the Montage keyboard and trigger sounds on an external synth I have setup to receive on MIDI channel 3, yet it also only receives one note for every four to eight keys I play. I've been reading about zones and I'm going to make sure I try every possible configuration of the Zone Master and zone settings later tonight, but I feel like I did this last night as well with no success. Again, just to reiterate, I am not using arpeggios for any of these parts. Thanks again for the replies. I really do want to figure this out once and for all and from everything I have read, it seems like it should be configurable to work for my setup.

You cannot use Hybrid as MIDI I/O Mode and the Zone Master at the same time. That is the source of some of your issues. If you are connected to a DAW and want to transmit to an external module, do not use the Zone function.

As soon as you activate a Zone Switch in your Performance, the MIDI I/O Mode (Single or Hybrid) will be overridden and the Settings you make for the Zone Setup will apply.

By definition, a Zone Setup implies MIDI I/O Mode being multi.

If you record Piano Part 1 and Strings Part 2 linked by KBD CTRL, Hybrid as the MIDI I/O Mode, channel selected = Ch1.
In order for them to play back properly, the KBD CTRL icons must remain active, and the Hybrid Ch should remain 1.
If you want to play an external instrument from the MONTAGE using Ch 3, use your DAW to route the incoming MIDI to the module.

You cannot use the Zone function. Trust me.

With Local Control = Off, the DAW software just sees incoming MIDI, it does not care what channel it’s on... use the MIDI Track to redirect your MONTAGE key presses to the external MIDI device on the MIDI Channel you require.

Leave MONTAGE Parts 1 and 2 linked, and because Local Control is Off, you cannot trigger them unless your DAW echoes the MIDI data back to the MONTAGE on channel 1. So unless you *select* that Track you will not be able to trigger the MONTAGE from the keyboard.

Create a new DAW MIDI Track set to receive MIDI from the MONTAGE on Ch 1, but route the MIDI Out to the external device (as soon as you do, you can play the MONTAGE keys but the external device will respond)... and you can set the channel to any channel you want... even Channel 1.. you set the MIDI Channel for each DAW MIDI Track. It will not interfere with the MONTAGE data... the DAW does the rerouting...

The MIDI Track is set to go to the specific external device, and to any specific channel you want to use in that device.
Local Control OFF allows you to separate the MONTAGE Keyboard from the MONTAGE Tone Generator, all routing connection are handled by your DAW?

Are you using Cubase?

Ok... So it turns out it was my complex configuration throwing everything off. I went home over lunch and tried some additional troubleshooting and found the culprit to be my iConnectivity mio10 MIDI router. There is a box that can be checked for "Running Status on DIN ports" within the iConnect software setup. It was checked as active, and had been for... well quite some time. But for whatever odd reason, the only device to be adversely affected by having this activated was the Montage (and I have in excess of 15 devices connected). Who knew?? Well, I am happy to say all is working as I initially thought it should! Next, I'll be trying out the new functionality of the USB to Device port with a couple of different MIDI controllers to see how I might further enhance playing of different parts on the Montage (and perhaps more specifically, utilizing a bunch of extra MIDI CC to control deeper menu items). Also, I'll be seeing if the sequencer will successfully sequence external synths. Is this possible? That would effectively put it in line with what the Fantom can do from a MIDI standpoint, just in a different way. Thanks again for the replies! Sorry it stemmed from my own oversight, but pleased as punch that I can now move forward doing the things I had hoped I'd be able to with the Montage. Cheers!