When spreading players into a chunk which is not loaded, if the target block has a non-solid block above it (eg: a snow layer, or tall grass), the player will become thoroughly "stuck" in the target block, unable to move until they have broken through the block they are stuck in.

This has been alleviated somewhat by the player now appearing to "slide out" of blocks which are adjacent to air, but this issue still effects flatter areas (eg: plains, tundra)

To reproduce:

1. Create a superflat world using the "snowy kingdom" preset (note that this issue effects non-superflat worlds as well, it is just easier to demonstrate in a superflat world)
2. open the world to lan and enable cheats
3. type: /spreadplayers 0 0 0 24000 true @s     into chat, and hit enter.
4. the player is almost certainly now "stuck" in a block (unless you coincidentally landed on a structure)
5. For a counter-example, type: /spreadplayers ~ ~ 0 10 true @s   into chat, and hit enter. As the area around the player is already loaded, the player does not become stuck in a block.

This issue seemed to first appear in 19w08a (19w07a does not appear to have this issue, but all subsequent snapshots that I've tried, do)