Flying up to top edges of old style world causes rapid flickering of screen (Epilepsy warning)

WARNING. This may cause seizures or eyestrain if you attempt, try at your own risk. The videos attached have the same risk.

Steps to reproduce - 

1. Create a new world, pick the old world style. Creative mode.

2. Enter world

3. Fly up to an edge or corner of the world, you need to be touching the invisible bedrock.

4. Fly up to ~128 blocks, your character should start twitching.

5. Leave the world

6. Re-enter the world, the screen will be flashing in between block textures and a above view of the world.

This has been confirmed to happen on Nintendo Switch too, see twitter link for example here.