If a player throws a xp-bottle directly upwards, the xp will get stuck in or on top of the block if the player has a block of air above his head.

How to recreate:

-Have a three-block high space, so that the player has a block of air above his head.
-Throw one or more xp-bottles directly upwards (Verticaly).

If there is a block on top of the other block, the xp will get stuck inside the block instead of just being on top of the block. When the player comes nearby it the xp that is in the block, the xp can't be pickud up, unless the block is broken.

Tested Minecraft Versions:

-1.16.1 -> Server and single player world, both confirmed.
-1.16.2 -> Server and single player world, both confirmed.

I provided a little testing world for testing the bug, if needed.