[Gameplay] Rek'sai W SFX

So, when you burrow as Rek'sai (in the past), you hear clicking sounds and calls that sound like echolocation as you move around. However, the last couple months, Rek'sai is totally silent while burrowed, and all the echolocation sounds are gone.

Is that a bug? I haven't tried any skins, but it for sure doesn't work on base Rek'sai.