18w09a - Water Lighting bug

If you place water down in a cave or come across it naturally, then enter it ONLY with the bottom half of the character, you still get the visual lighting effect as if under water. This may be due to the hit box of the player being in the water instead of the view point of the player. The attached video shows how to re-create this.

https://youtu.be/BgSnODFysqg