Item's position is not correct. this happens when an item is tossed against non full blocks and at chunk borders rarely. The video shows the carrots can't be picked up or destroyed as their position is not correct. although the item physics works as if the item is at the bad position.
when the player moves above to the correct position, he was able to collect it.

visual
https://www.youtube.com/watch?v=klHpyw1ndpc&feature=youtu.be