I saw that the only reason emissive elytras work at all is because they (kinda?) just worked out of the box with the CIT and everything else this mod already does so no biggie if it's too complicated to fix. I noticed that using an emissive elytra texture simply stops working if you crouch. I tried every combination of the size fix and z fighting settings to no avail.

does this still happen with the 2.6.1 beta on curseforge?

It looks like it might be fixed, but I can't really tell too well because the z-fighting fix option appears to be gone in that version so I can only see the emissive layer from odd off-angles in f5 mode.

Isn't this fixed?

it has in a dev build not in stable, i'll close then

fix in V4.0