Please, help me understand sample start offset in Hise

[arcy]

Hi, I'd like to modulate the sample start to avoid phase issues using unison voices. I follow the same steps from Kontakt: Choose a sample portion with sample start mod and modular with a random envelope the sample start. In Kontakt it works well and phase issues disappear, whereas in Hise it seems that this method doesn't change the result...what's wrong?
Thanks!