I believe this item has a chance to drop black hearts on hit as well. There was a ton of black hearts dropping out of Isaac when Tyrone took it on one of his streams.
We keep an eye on this effect but until then, please not add it as we have no way to verify that.
Despite me not having defeated Hush with Eve, I have received this item in a Devil Room. Possibly it unlocked because I converted my stats from Rebirth?