Try un-subbing from the addon and uninstall any Genshin models from your Gmod folder. Wait for a few minutes and re-subscribe. When you're re-subscribing, make sure you downloaded the addon fully before launching the game and joining a server. The addon on your side may have not updated properly yet.

I've already tested the models numerous times and the blush emoji materials works just fine.
https://i.imgur.com/HwRCVcb.jpg

If there's any more issues let me know. Also, tell me which character has the bugged out material, so that way I can narrow down the search.

That might occure especially due to updates (if there are similar file names, sometimes vmt. changes are not noticed by workshop).
As 8sianDude said, unsubscribing and cleaning cache of addon might a solution. To do that:

1. Unsubscribe
2. Log into g-mod
3. Open console and type "menu_cleanupgmas" (afterwads you might double-check your "...\Steam\steamapps\common\GarrysMod\garrysmod\addons" or "...\Steam\steamapps\workshop\content\4000\2252304893" folders to make sure that there is no more existence of .gma files)
4. Re-subscribe.
5. Profit.

If the problem still occurs, we'll check around sharp edges of pack again, but regardless, on my testing, everything seemed to work fine.

I just repackaged all the material files again and pushed another update. Hopefully it's fixed this time.