Channel numbers swapped in the mixer

Cubase 5 on a Windows 7 PC:
From time to time when I duplicate channels the order of the resulting channels will be mixed up. However, I’m not able to reproduce this in a reliable way. I took a screenshot:
kanäle vertauscht.png
I had the issue with Cubase 5.0.0 and still have it with 5.5.3. Is there anyone else with this issue?

IIRC, it has to do with if there are hidden channels in the mixer.

I usually never use hidden channels in the mixer, but I’ll check if used them the next time I have this issue.