Hello,mojang. The mob in my survivor mode game drops nothing. And a lot of villagers in my trading system disappear. Can you help me?

Mojang. I got two problems. First, the mobs in my survivor world does not drop anything. ( like a iron golem does not give me any iron) 

second, some villagers in my trading system disappear. Can you help me check it?( I feel like it’s a bug)