Figured it out, looks like it’s bug in the newest build of HairWorks for maya “Maya_2016_64bit_1.1.11028.12482”
I tried it in maya 2015 aswell with the newest build. Same.
So I downloaded an older build “Maya_2016_64bit_1.1.10506.22462” and the bug was gone.
I would report it to nVidia but don’t know how!
Cheers.