Hey I'm the emissive guy again (from the FirstPersonMod). Really sorry for bothering with these low priority problems. I just leave it here and hope we will have a solution one day.
When this mod and Optifine is installed, nothing else, and I hold an emissive tool, or item? (didn't tested for other emissive items, but they are having te same problem probably) the normal and the emissive layers start to mess with each other. I have no clue how this happens. It looks like one of the layers is moving for some reason and it glitches into the other.
I dont have a gif or vidoe, but have two pictures. On pic1 its normal then on pic2 it flickers and then it starts again.
Edit: Forgot to mention it's only in third-person, it works fine in vanilla first-person.

Gonne close this because of Optifine. ETF should probably not have this issue.

The issue probably is that optifines rendering is not using the correct angle. Same thing as in tr7zw/FirstPersonModel#127 , I have no clue how to fix that correctly since optifine is such a black-box.
Try messaging sp614x(optifine dev) on discord, it worked for me, i fixed 1 bug with shader.

The issue probably is that optifines rendering is not using the correct angle. Same thing as in tr7zw/FirstPersonModel#127 , I have no clue how to fix that correctly since optifine is such a black-box.