Y’all should stop listening to streamers spreading nonesense across their communities. It’s only testable for now on raid items because the whole loot acquisition isn’t testable on the PTR right now.
https://eu.forums.blizzard.com/en/wow/t/corrupted-items-details-and-feedback/97588
Blizzard said it would matter for every season 4 drop, even heroic darkshore warfront.
The drop rate is still unknown as the PTR items aren’t true drops, they only exist for the sake of testing the corrupted items