HairWorks wrong shading normal with left hand y-up conversion

I’m integrating HairWorks into my company’s Engine, which uses a Left Hand, Y-Up coordinate system, when I use this conversion combination, shading normal seems wrong on some spot.

when I use other conversion combinations, every thing seems fine.

I uses hairworks 1.2.1, and I didn’t do anything except loading asset, creating instance and rendering it.

How to reproduce:

Load my file into one of NVidia’s sample project (all of which uses LH Y-UP),
and output “NvHair_ShaderAttributes.N / 2 + 0.5” will yield similar result.

wrong normal:

[url]https://1drv.ms/u/s!AlluoglYGGHYktoytc6ge1LrCLQ30w[/url]
[url]https://1drv.ms/u/s!AlluoglYGGHYktozZNTdq8UfWoqKhg[/url]

correct normal when I use right hand z-up:

[url]https://1drv.ms/u/s!AlluoglYGGHYkto0WiCRrbRp3fG9hQ[/url]

some of my files:

[url]https://1drv.ms/u/s!AlluoglYGGHYkto2bk0hMrKZbo1Qyg[/url]
[url]https://1drv.ms/u/s!AlluoglYGGHYkto1umH6vRzIEZpVdg[/url]

why other people can’t see this post? strange.