Flying player is not standing up while being on ground in one block heigh spaces

The bug

In the latest snapshots the hitbox soze of a flying player was changed. Due to this the player was able to fly through one block heigh spaces. However if the player touches the ground while flying through a one block high space, only the model shows the player standing, but the player is still kind of flying (you can still experience MC-91365).

How to reproduce

See Minecraft - Walking in one high space with elytra