Spiro Renard
Summary:
The VRChat SDK is causing Unity to falsely detect prefab overrides when no actual changes have been made. This issue occurs both during general SDK activity (not just when opening the SDK tab) and specifically when uploading or updating avatars. It often flags the Avatar Descriptor component as "changed," even when untouched.
Steps to Reproduce:
  1. Open a Unity project with VRChat SDK (SDK3 - Avatars).
  2. Create or load a prefab-based avatar.
  3. Upload or re-upload the avatar via the SDK.
  4. After upload completes, observe that the avatar prefab now shows "Unapplied Overrides" in the inspector.
  5. Open the prefab and inspect the VRC_AvatarDescriptor — Unity claims it's been modified, even though no changes were made.
Expected Behavior:
Uploading or interacting with the SDK should not trigger false prefab overrides when no values were changed. Avatar Descriptor and other components should remain untouched unless explicitly edited.
Actual Behavior:
Prefab instances are flagged with "Unapplied Overrides" after uploading or interacting with the SDK. The VRC_AvatarDescriptor component is frequently shown as modified, despite no visible differences. These overrides appear without user input, leading to confusion and unnecessary prefab management.
Known Triggers:
  1. Uploading or re-uploading avatars.
  2. SDK interactions during project use (not limited to opening the SDK tab).
  3. SDK updates that introduce new systems like (often re-introduce the bug): PhysBones, Constraints, Per-platform Avatar Overrides
Impact:
  1. Disrupts normal Unity workflow and prefab integrity.
  2. Forces creators to manually check or apply overrides to maintain consistency. (Sometimes not even working and getting stuck in an override change loop)
  3. Risk of unintentionally applying unwanted changes or overwriting important prefab data.
  4. Time-consuming and frustrating for creators managing large or complex prefabs.
Additional Notes:
This issue has persisted across multiple SDK updates and is easily reproducible. It appears tied to how the SDK modifies or refreshes component data internally. Given how fundamental prefabs are to Unity projects, this issue should be considered a high-priority bug — especially for avatar creators relying on clean and reliable prefab behavior.