I can confirm that there either is a bug or too strict rules regarding this feature.
I often have this problem. And I solve it the same way as Lydiot. I copy everything on the tracks I want to merge to new mono tracks. Then it works
Sometimes mono events are on a stereo track after a aaf import. That also must be a bug, but if this happens, merge doesn’t work.
I’ve even had this bug up when testing first a split from multichannel, then trying to merge back the recent split tracks and it throws the error.
IMHO there is two issues here. Some kind of very weird timing issue bug and also a feature request. Nuendo should treat us like profeesionals. Nuendo should just merge our tracks when we tell it to.
Don’t boss over me! If I want to merge two tracks where the one track only have a short event, it should just merge them. Even if I’m wrong, I want it to do the task.
My 2 small coins.
/Pål