When a bee isn't pathfinding, it will fall like an iron golem instead of slowly floating down like a chicken, parrot, vex, or blaze. This causes bees to awkwardly drop out of their nest/hive instead of smoothly hovering down. It also happens to baby bees when they're born. The best way to reproduce this is to run the following command:
/summon bee ~12 ~12 ~
The bee will fall quickly instead of slowly fluttering down. Even though bees don't take fall damage, it looks painful; poor bees.
Linked issues
Comments

Confirmed/Reproduced in 20w29a.
Can confirm in 20w51a.

Can confirm in 21w40a.
In 20w28a