If anything, the behavior of Logic seems even more strange to me. I'm surprised anything using NRPN works with if Logic isn't sending the full NRPN message to the synth. If this actually works, you might be able to use a script, plugin or something like the MIDI Solutions Event Processor to simply block CC38 from getting to the synth from Cubase, emulating the behavior of Logic. Someone more well versed in MIDI might be able to explain that one..

I looked through the MIDI CC charts of some of my hardware synths, and all of them indeed skip CC# 38, 6, 99 and 98. Really weird that Novation would make this mistake, especially since the synth actually does use NRPN.

No issue here with the Summit in Cubase 14 Pro, I just tried a quick test recording the filter cutoff (14 bit midi) and vca gain (NRPN). The synth is setup to send and recieve NRPN, all records and playback fine. No issues with weird stuff happening when operating any of the buttons on the front panel either. If I do want to go in depth with editing recorded automation with it I'd probably use Sigabort.

https://sigabort.co/midisynth_peak.html

Thanks for letting me know. If you have a moment to slap a midi monitor on it, I'd be curious if you're seeing CC 38 sent with pressing buttons on the panel, and with OSC2 turned up to be sure. Specifically, according to the aforementioned shared thread from another forum, it appears to be a conflict with CC 38 being occupied by OSC2 Mod Env2 > Depth (so if I load a patch which does not have OSC2 turned up I won't hear any issue). I checked out the Summit Manual and it looks like it's the same CC 38 value for that just as it is on the Peak.

If that still works for you then I would have to wonder if they snuck a fix into a firmware update only for Summit (since the user on that forum mentions having a chat with Novation, specific to Summit), and neglected to reflect this change onto Peak. Probably grasping at straws but it's pretty weird behavior, and I don't think it's an issue with my specific hardware. Hoping to hear back from them next week.

The preset definitely used oscillator 2, I remember checking the level and it was at full volume. If I get a chance I’ll check the buttons with the midi monitor plugin.