[Shader] at_midBlock breaks on X and Z axis in 1.21

[GeForceLegend]

Do not click links like Download LINK In the installer menu, select "gcc." in comments. I don't know where those links from, but mediafire already marked files in those links as dangerous.

Description of Issue

X and Z axis of at_midBlock on tons of surfaces are +-96, even though they are expected to be +- 32 as they are just common vanilla blocks

Steps to Reproduce

1. Using https://github.com/GeForceLegend/SEUS_PTGI_GFME
2. Voxelization is completely fuked up, as it's using at_midBlock on Minecraft 1.17+ for Iris compatibility

OptiFine Version

1.21 J1 Pre1

Installation Method

Standalone

F3 Debug Screenshot

Additional Information

Renderdoc reference showing wrong at_midBlock on tons of vertex

[KaiAF]

Do not click the link that was just sent.

[GeForceLegend]

Do not click the link that was just sent.

It will be better deleting those messages send by bot in Optifine discord server

[sp614x]

Fixed, coming in next preview