• Minecraft 1.12.2
• Forge 14.23.5.2860
• Custom Player Models 0.4.3a
• AutoRegLib 1.3-32
• Quark 1.6-179

Using Quark along with CPM is causing render issues, including:

• Armor not showing up at all, even for models that don't touch the armor
• Hand items not showing up if any armor is worn
• Entities being rendered in strange positions depending on where the camera is and which way it's facing
• Intermittent inventory screen problems, such as items appearing off to the left of the window
• OpenGL error logspam, by my math about 250 times per second (sometimes with only the last two lines, and never with anything helpful like a stacktrace...):

  [13:32:27] [Client thread/ERROR] [net.minecraft.client.Minecraft]: ########## GL ERROR ##########
  [13:32:27] [Client thread/ERROR] [net.minecraft.client.Minecraft]: @ Post render
  [13:32:27] [Client thread/ERROR] [net.minecraft.client.Minecraft]: 1283: Stack overflow
  [13:32:27] [Client thread/ERROR] [net.minecraft.client.renderer.entity.RenderLivingBase]: Couldn't render entity
  java.lang.ArrayIndexOutOfBoundsException: null

I couldn't identify a particular part of Quark to be causing this; it still happens even after disabling literally the entire mod's content in its config. Only removing Quark or CPM stops it.

This is a purely graphical issue, with no impact on gameplay, not even lag (surprising, given the logspam).

1.16.5 and later Quark plays fine with CPM. This seems to be specifically a 1.12.2 issue.