Large ferns no longer drop seeds

As expected, grass, tall grass, and ferns have a chance to drop wheat seeds when broken in survival mode. However, large ferns apparently do not drop seeds; I have broken dozens upon dozens in survival mode, and either I'm incredibly unlucky, or large ferns have a 0% chance to drop wheat seeds. Is this a bug, or are small ferns not supposed to drop wheat seeds even, as they were renamed from "seeds" to "wheat weeds"?