all right this one is a bug I notice for quite some time in sooner Cubase versions as well.
It seems only to happen using a large amount of VSTi-Racks.
It is hard to re-create so I might send my project to the support if necessary.
It looks like this:
- I select VSTi rack #68 / Midi Ch.1
2a) I double the track, Name and channel settings should be the same but my Midi OUT now refers to VSTi #66 / Midi Ch.1
2b) I add multiple MIDI-tracks. Usually they all inherit the MIDI-OUT and increment the Midi Channel. But the OUT is set to VSTi-Rack #68 again.
Also the manually correctel midi OUT setting is either not saved in the Project or it is reset on load to #68 again.
I recorded 2a as a GIF