Waterlogged blocks sometimes use a biome-tinted version of their own texture instead of the water texture, leading to this effect that could be a non-RTX alternative to water reflections, if the transparency of the texture were the water texture.

STEPS TO REPLICATE: Step 1: Place waterlogged blocks

Step 2: Repeat until waterlogged block uses its own texture tinted to the biome you are in, instead of the water texture.