Nuendo’s mixer can get out of sync. The tracks in the mixer are in a different order then the tracks in the project. Not sure how I managed this yet, but will post repro when I figure it out. This issue is not new to 5.5, I’ve seen it for some time now.
be sure that there are some Audio Tracks in the upper, and in the lower Track List.
right-click an audio track in the middle of the upper track list, and add a new group channel track.
The group channel is created at the bottom of the lower Track List, but the position in the mixer will be an absolutely different one!
not the same thing, Group tracks and/or fx tracks always get created on the bottom. (Not a fan of this but got used to it)
This one is in regards to regular tracks, they get created and you move it in front of another in the project list but the mixer still shows it at the prior location, if you move it again the mixer refreshes.