Water color on maps ignores biomes

The colour used by water seems to much more closely resemble the default water colour from 1.12.2 and prior, rather than the updated 1.13 palette (and even in 1.12.2 and prior, would not respect swamp tinting). Expected behaviour would be that it would change on maps to respect its actual appearence, but it does not.

Bedrock Edition is unaffected by this bug. For example, here's a visible divide between two different ocean biomes: