Attempting to build a Quest compatible avatar makes Unity want to delete everything?

I am having this error show up whenever I switch the building target from Windows to Android. if I allow the SDK to auto fix the issue, it just deletes the entire avatar.

  • I used the same exact SDK file to create my current PC-only avatar, and it does not give me this error message when I switch the building target back to Windows.
  • I am using the SDK provided mobile shaders for the materials and nothing else.
  • This avatar is a custom model. And all rigging shows up fine when in the configuration menu.

No one I’ve spoken with knows what this is, nor why it’s happening. Any ideas on what is going on and how I can fix this issue?