No arranger track or transposition track after importing


if I import a Sequel 3 Project in Nuendo 5.5 I can’t see the arranger and the transpotion tracks.
When I try to add a new arranger track, Nuendo says, there is an arranger track in the project :cry:

If I open a new project in Nuendo, all works fine. It seems to be a bug here.

Or, what can I do ?

Thanks a lot and regards,