[1.19.3/Basic v2.1/Enhanced Default v1.15] Mob emissive textures broken; not glowing

[Glorax]

In all versions of Basic and Enhanced Default, mob emissive textures don't glow. This effects mobs like spiders, endermen, and wardens.

The emissive textures will temporarily reappear on certain mobs (like spiders) if you stand near them with a handheld light (tested with torch). As soon as you switch to holding something else the emissive textures vanish again, like a lightswitch has gone off. Placed torches don't make the textures appear. Sunlight also seems to make the textures reappear.

Tested using OptiFine 1.19.3 preview 5.