I got rid of it by setting transform and rotation to zero (freeze transform). (another prerequisite found 
)
Flawless export but I am now back to the old error.
As it looks like the HairDescriptor has changed, I can´t test with the 1.1-viewer.
However, somehow my FlightControler wants to play with the new viewer too and rotates arround all the time.
Interesting that the axes are changed by the same number.