i use the Mine little pony mod found here https://github.com/MineLittlePony/MineLittlePony/releases

the issue i am having seems to be that the camera is just slightly inside the model's head

this worked in 1.19.0 just fine, the behavior popped up with
firstperson 2.1.2
mine little pony 4.6.1

MineLittlePony never was officially supported. Nothing about the head hiding was changed for quiet some time, so might be some change inside that mod.

according to a recent update, the head position was changed slightly. i guess i will go give them a poke

Also added some developer API in #300, so the mod can better add support for it. Apparently, the mod is not on Modrinth or Curseforge, so won't be looking into it more right now.