Hello, sorry for the delay.
Here I'm trying with Ornatrix V3 and Arnold Core 6.1. It seems to be working correctly:

Try upgrading Arnold to 6.1. I'm also including the file so you can test.
When exporting the hair, make sure to set the Viewport Count Fraction in Hair from Guides to 100%, so it exports all the strands.
Also notice that in new Arnold versions the .ass export steps are different. Now you go to Arnold menu > Scene Export > Export Selection to .ass.