On Win11 PC & C15 Pro both latest updates.
On a Project with two MIDI tracks routed to the same multi-timbral synth Roland Fantom G8 sending on two different MIDI channel outs.
One track has Breath, Expression, Volume and other Continuous Controllers data and is MUTED.
One MIDI track has no CC data and is NOT MUTED.
Press play and things are normal, the track with CC data does not sound or update the Volume on the synth for the muted track (can be seen on the synth screen fader).
Stop.
Move the mouse and select different points in the timeline.
Cubase sends out the muted tracks CC data, changing parameters in the synth.
If by any chance both MIDI tracks were set to send on the same MIDI channel, the MUTED track CC will be sent out when selecting a different place in the timeline with the mouse. So all of a sudden the NOT MUTED track will not sound (volume at 0).
Go to preferences and under Chase Events, tick off Chase Controller/Expression maps. Apply, OK, the ISSUE no longer occurs.
It drove me crazy trying to figure out what was going on and once I deleted the CC data from the muted track the problem stopped, giving me a clue to what was going on.
Deactivating the Chase Controllers eliminates the problem but it introduces a different problem if using a synth with CC data by not updating with the timeline when stopping or moving forward and back on the project.
This Issue is erratic. Even if setting both tracks to different MIDI channels weird stuff can happen with the levels on the NOT MUTED track when selecting a different point in the timeline with the mouse.
Why is C15 Pro sending/chasing CC data out if the tracks are muted and why does sometimes send it to a different MIDI channel???