Describe the bug
The resource pack Better Cats! changes the model of cats and adds custom parts not part of the vanilla model. The eyes and whiskers do not get rendered when using the new Iris beta 1.7.0 version.

List and link to broken resourcepacks
Better Cats!

Expected behavior
The eyes and whiskers should be visible.

Screenshots

[1] Iris 1.6.17 - The cat's eyes and whiskers render normally.

[2] Iris 1.7.0 - The cat's eyes and whiskers do not render.

[3] Iris 1.7.0, EMF/ETF 2.0/6.0 config screen, custom gui resourcepack - The cat rendering as intended in front of the eye- and whiskerless cat in the background.

Update: [4] Iris 1.7.0, EMF/ETF 2.0/6.0 config screen, custom gui resourcepack - The cat's eyes, whiskers, collar and snout rendering in front of the eye- and whiskerless cat in the background.

(please complete the following information):

• Minecraft Version: 1.20.4
• EMF version: 1.3, 2.0
• ETF version: 5.2.3, 6.0

Additional context

This bug does not occur when using Iris 1.6.17 and also does not occur in the EMF config screen.
EMF 1.3's config screen only renders the missing parts (whiskers + eyes) and the ears. The collar, too, if tamed.
EMF/ETF 2.0/6.0 config screen sometimes renders the cat fully and correctly (screenshot attached) and sometimes it shows the same behaviour as EMF 1.3's config screen except that it also renders the snout and nose.

Update: The latter (Screenshot 4) happens specifically and only when the emissive rendering mode is set to Brighter. Setting it to Default causes it to render normally (Screenshot 3).

The eyes and whiskers get stored in separate texture files and are not part of the main cat texture file.
The resourcepack uses the Optifine random mob texture feature. Disabling it does not fix the bug.
Both the cats' main texture and separately the cat's eyes use this feature.
The eyes also use the emissive texture feature.

Newest commits of ETF fix this issue. (: Thank you! <3

This is known and requires changes on my end once it's out, I'm looking in to doing it for the beta but I'm doing some other stuff first

this the distant horizons beta?

Yes.

EMF/ETF 2.0/6.0 full release has fully fixed this issue.