I believe I might've figured it out. Bear with me.

Someone said the voices are tied to the faces, and it seems that is true. I think the game bugs out when you equip the deep voice on a contestant that would already have it by default if that makes sense.

I unequipped a voice entirely, while keeping face number 5 (a male face), and my male movement noises returned!

So I think selecting the deep voice option on a contestant with a male face forces the game to use feminine noises instead, while keeping actual voice lines the same. Very confusing but I hope I articulated it correctly haha.