Total head-scratcher here. I'm using latest Studio One 4 Professional on an i5 iMac with latest Mojave, my MIDI controller is a Nord Piano 3 connected via USB, and I'm using it to record MIDI for Garritan CFX piano VI (latest version, and I've tried both AU and VST) which is instantiated on a standard instrument track.
The Nord has a continuous-type sustain pedal, generating about 6 different CC64 values on the up and down stroke. If I observe what S1 is receiving from the Nord via the MIDI monitor (or in another DAW) it's really only these CC64 messages (plus note on/off of course).
When I record a sustain pedal press on the Garritan CFX track I get a MIDI CC automation lane in the instrument track called Sustain Pedal OnOff, showing the continuous pedal values - this is expected. But... unexpectedly I also get another lane called 'Current Sustain', which shows a similar but not identical curve associated with the pedal press.
And here's the weird bit: when I play back a song with these pedal messages, the 'Current Sustain' values (or at least some of them) flow into my Undo History as if they were user actions. It means that when I'm editing a song that has extensive use of the sustain pedal my Undo command becomes virtually unusable for any normal tasks - it just becomes a long list of 'Set Current Sustain to 1.0' and similar.
If I record exactly the same thing from the Nord with any other virtual instrument (I've tested with Presence, Synthogy Ivory, Pianoteq 6, lots of different synths) I do not get this spurious Current Sustain behaviour, just the Sustain Pedal OnOff data as expected and no weirdness with Undo history.
So it seems that CFX alone is somehow injecting its own MIDI data types (goodness knows if they're CCs, or what), into Studio One. What's more it seems to be doing it in realtime, because if I delete all the 'Current Sustain' data and even remove the MIDI CC lane, this data still goes into my Undo history on playback.
Am I missing something really obvious here? I always assumed that the Instrument Track was just a place that incoming MIDI data or user-generated automation curves was stored, acting as a master to any virtual instrument 'slave' associated with it. But in this case it's like the instrument is answering back. I don't understand the mechanism behind how that could happen, and I actually just really want it to stop!
Any thoughts or advice on this would be really appreciated. Thanks very much. Robin