The sky the the Warped Forest biome is rendered bright purple whenever the player is effected with night vision.
To recreate: go to the nether in snapshot 20w06a and find a warped forest. The effect yourself with night vision (I used the command /effect give @s night vision 1000).
just realized I accidentally created this in the bedrock section so ignore this post. I am reposting it in the java section. https://bugs.mojang.com/browse/MC-171550
Why is this in the Bedrock Edition section? You should report it here:
https://bugs.mojang.com/browse/MC