Latest iris causing glow errors.
They changed transparency apparently
Iris 1.4.2

Iris 1.4.3

I also encountered this problem, but in fact, if the color to be illuminated is pure, such as #00FFFF, you will not encounter this error.
I think it should be a problem with iris, but I haven't checked whether the glowing eyes of entities such as EnderMan are normal.
This must be the problem
https://github.com/IrisShaders/Iris/commit/c695022943497b067568cf17e286487516a86123
Doesn't happen anymore in recent versions.
Doesn't happen anymore in recent versions.
The problem still seems to exist
What is your Iris version? Can you create a small example project that shows this issue?
What is your Iris version? Can you create a small example project that shows this issue?
The iris Mod version I use is 1.6.6 CPM Model: https://github.com/FurryRbl/OpenAssets/blob/main/old/OC/Personal/Minecraft/SharpIceX/Model/CPM/SharpIce4.0.cpmmodel CPM Model Project: https://github.com/FurryRbl/OpenAssets/blob/main/old/OC/Personal/Minecraft/SharpIceX/Model/CPM/SharpIce4.0.cpmproject