Endermen doesn't drop ender pearls

We we're playing on a Multiplayer world. The device that has the saved file was the Samsung Galaxy Note 5 and the other device playing is a Xiaomi Redmi 5. 

Since the 2 previous updates, we noticed that Endermen are not dropping Ender Pearls. We are using Diamond Swords with Looting 2 and 3 and as well as regular iron swords. After several Minecraft nights of hunting Endermen and not getting ender pearls, we decided to get some with trading from a cleric villager, find the end portal, kill the ender dragon and farm for pearls in the end. We killed lots of Endermen for about 30 minutes and still not a single Ender Pearl dropped.