Mods known to cause this issue:

• Minecraft Dungeons Armor

Fixed(my cancel point was set up in a stupid way, now it should catch all mod armor).

Yeah, I am in contact with the BetterCombat devs, and I am aware that my current workarounds don't fully work there. The next update will contain the Fabric API integration to hopefully better prevent them from rendering.

Hey, I have some more details regarding this issue, as more and more people are pointing it out.

I would recommend looking at ZsoltMolnarrr/BetterCombat#27 for more examples/screenshots of what is happening here.

In my case for Mythic Metals, my armor uses Fabric API's ArmorRenderer to register custom meshes as BipedEntityModels. I believe due to that implementation the armor is rendered unexpectedly in quite a few scenarios.

From reading some of the srouce code, this is also what happens with Aether Reborns Phoenix Armor

Immersive Armor does something a bit worse, which is implementing their own ArmorFeatureRenderer

Adding compatability for Fabric API would solve most of these cases. I think a potential solution would be considering writing a Mixin into it, or some other attempt to try culling/stop rendering the head layer while in first-person (this would have to happen late somewhere).

Hopefullly this sheds some light on the issue.