I have a lot of bees in my minecraft world, but one day I noticed all of them were just missing from their hives. I collected quite a lot of new ones, but some in-game days later, all except one were missing again. As I was venturing throughout the world one day, I saw a huge group of bees just wandering around aimlessly away from my home some hundret blocks away. I am quite certain these are my bees, I have never seen so many bees spawn naturally.They all were full of pollen, but none of them returns home.

Screenshots of the big group attached, as best I could could get them.