Apparently I've been noticing something is wrong with my bee nests on Bedrock Realms. The bees I've been housed it in Beehive gone. I've inspected the original source of the bee nest that I reproduced the bee from also left with 1 bee. 

To troubleshoot this matter I've been reloading my realm with older backups. It is confirmed the bee is no longer there when I loaded the May backup. It was at the time my bees work diligently to gather honey. It seems there are no traces nor sound produced from the beehive.

Also, I've loaded the oldest map that contain a bee house in it. The only bee that appear is 1 bee only. All 20 other bees gone.

Another thing: the bee seems to be stuck without any house after it's spawned. Even though the bee hive was added afterwards.

Edit: In detail. Creative mode flat land. 

1. Hive was placed x 2 unit.
2. Bee was spawned 2 + 2 + 1
3. The last bee seems to be stuck 'homeless' and wandering around.
4. Tried to add another hive/nest. Added another spawn of bee. The latter entered the hive, the bee on #3 still not enter.

Update: 
Note: All of the above was tested both on Realm and Singleplayer Mode.

Another test has been conducted to verify the bee situation. Apparently for my current map, there's only left with 1 bee. The older map is the same, but both behavior are erratic. 

• The current one keep flying even when there's a flower at my hand. (I believe the bee should be closer to the ground while the flower was held.
• The older map stuck on the ground, by default. 

Both can be concluded that they both has a unit of bee nest (the naturally generated house). I attached another photo as a reference for this case.