Version of ETF - 1.20.2-5.2.1
Version of EMF - 1.20.2-1.2.3
Used Quilt loader. Of the installed mods, only ETF and EMF

Describe the issue

With this mod, some entities with custom names will have vanilla textures, instead of ones specified in .properties. I assume that happens because ETF processes names in .properties that use spaces without ipattern incorrectly. This issue doesn't exist in Optifine.

For example, with this mods, texture of a creeper with:

Name in the game: «Abomination»
name.X=Abomination
Will loaded CORRECTLY

Name in the game: «Flaming Horror»
name.X=Flaming Horror
Will loaded like VANILLA ONE instead of custom

Name in the game: «Colossus of Chaos»
name.X=ipattern:*Colossus of Chaos
Will loaded CORRECTLY

With Optifine textures in all cases are loaded CORRECTLY.

How to reproduce
You can download this resource pack, use the same versions of ETF and EMF, and name creepers the same way i mentioned earlier. The Flaming Horror will have a vanilla texture. Then you could open the same world with Optifine and all creepers will have custom textures.

Fixed in 6.0 version