I've updated my single player world to 1.16.1 today, of which had quite a number of bees in it already surrounded by lots of flowers so they would never 'get lost' or not return to the various hives available. I've noticed today that all my bees have disappeared, of which I found only two left about 50 blocks away in a forest (my hives are in a mountain biome). I tested it by breeding the bees, of which the baby completely disappeared after about 10 minutes and they all continued to pathfinder away. I tested it by breeding more and moving them to a new area with new hives and a farm, they completely flew away multiple times (not even in the direction of their 'original' hives) and don't seem to claim any hive as their own, even when it was raining a number of the bees just floated around outside of empty hives instead of entering them