Entities, when you press q and throw something, are almost invisible. The only way to see them is from a certain angle (close to 90 degrees). Not all thrown items behave this way. Only the ones which don't exist as real blocks (eg rotten flesh, and lava bucket, not fence, or cobblestone)

How I saw the bug: I was looking at the new update where villagers were breaking mature crops with their head (so cool) and then I couldn't see the actual wheat. I got close to them and the crops entered my pockets, suddenly becoming visible as they move into the pockets. I switched to creative and started flying, only to find them becoming visible at a specific angle (I can't measure it though, but it's 45<x<90 degrees)

What actually happened was...:
I believe this is unrelated to the villagers. I threw inventory items and they had the same effect.

Steps to Reproduce:
1. Press q to throw an entity that is not a block (eg milk bucket, sword)
2. It will be invisible but its there
3.It becomes visible when its moving towards you entering your pocket.

Pictures
The pictures explain that after I throw, I can't see it, until I fly up and look down. in 12.10.00, there is the water bucket at the bottom right. In 12.10.09, the same thing but a lava bucket. The other two pictures were just when I first discovered the bug, as this whole field was full, but I only saw the entity from above.