MiniHUD 0.19.0-dev.20211027.183903
Minecraft 1.17.1
System Details from F3+L

This is part of the surface of a Despawn Sphere rendered using Fabulous graphics.

This is a similar part rendered using Fancy graphics.

Expected: At least Fabulous graphics should:

• Render the shape underwater when you are above water and vice versa.
• Render any water behind the shape as well.

Actual:

• Fancy graphics renders the shape, but only above water, but it also renders the water behind.
• Fabulous graphics renders the shape, but only above water, and cuts off rendering of any water that's behind the shape.

To reproduce:

1. Go to an ocean or a river.
2. Use MiniHUD to set a Despawn Sphere at your current position (any other shape works fine as well).
3. Use vanilla's elytra flight, Creative Mode, or Spectator Mode, or Tweakeroo's free cam, to view the surface of the Despawn Sphere next to the surface of the water.
4. Notice the rendering errors described above.