Hi Steffen,
Thanks for your question here!
I have checked your file that you sent in in your case about the same topic. Based on the file, the problem is caused by the Global Coordinate Reference Surface being on the Image surface which is at infinity. This reference at infinity messes up the Graph view of the 3D Layout plot. You should not select the reference to be at infinity.
To resolve this issue, please change the Global Coordinate Reference Surface in the System Explorer to a different surface, e.g. Surface 1:
Then you will see the correct design in the 3D Layout too:
Best,
Csilla