Zombies that turned into drowneds don't drop items

I was searching for tridents, but I couldn't find one. I went to my testing world and I found out the reason. Zombies that turned into Drowneds don't drop anything but XP. I tested with regular Drowneds, and they still drop items.

(There wasn't a 1.5.0.0 option, that's why it says 1.2.20.2)