The sun has a sudden change when the player goes in water

Please explain in words where's the difference, cannot see any.
Keep in mind that the water in Minecraft has (like IRL) a higher refractive index as air.

When underwater the sun is bigger, having a yellow outline, which doesn't exist if the player watches out of water. The size may have something to do with the refractive index but it cannot be the cause of the yellow outline.

Looks intended to me. The bigger size is caused by higher refractive index, outline: idk:

You can also see the yellow outline during the sunset/sunrise.