Block shadows cause opaque water in Vibrant Visuals

In the Vibrant Visualspreview, block shadows (ie. the simple per-block shadows that impact actual in-world block light levels, as opposed to deferred lighting's real-time shadows) cause screen space reflections (SSR) to render incorrectly, causing strange visual artifacts whereby shadows appear white/opaque. In standard gameplay, this issue is visible whenever blocks overhang a body of water, and can also be obvious underground in caves.

The issues persists even if the blocks causing the shadow are far above and off-screen, implying that it is not a technical limitation of the SSR tech. But if there is a technical reason behind the issue, then the shadowed areas should be made darker rather than lighter.

1.21.130.26 slightly improved the issue by restricting the opaque regions to only where there is at least one block of margin in the blocks casting the shadow, effectively insetting the opaque regions by one block. However the issue is still present.

Setting the sky color in client_biomes.json to black seems to resolve the issue, but is unworkable due to its other impacts on the graphics.

Steps to reproduce:

• Import the included example world file (which includes an example deferred pack), and look toward the cobblestone overhang above the water.

• OR: Apply any deferred lighting-enabled texture pack that has water reflections properly configured, and find an area of water that has blocks above it.

Observed behavior: the shadowed area appears very bright and lacks the correct environment reflections.

Expected behavior: the water should reflect its full surroundings regardless of whether there is a block shadow on it. If this is infeasible, block shadows should cause water to darken rather than lighten.