The grass block shouldn't have the reflection.

Water Reflection (Image flipping):

Water Reflection (Ray tracing):

Versions:

• Minecraft: 1.18.2
• MakeUp UltraFast: 8.8e
• Iris 1.6.2

Hello. It's not a bug, it's the way the reflection works in "Image flipping" mode.

It's literally like taking the image on the screen and turning it upside down.

The raytracing method is a bit more sophisticated (but slower), hence the alternative.

Neither method is a "real" reflection, the shader only uses the information that is on the screen.