If an AnimatorController is assigned to the avatar’s Animator, any properties animated by that controller will revert to their previous state when modified in the Inspector while the SDK Builder panel is open.
This issue occurs with both VRChat-provided components and custom components used in non-destructive workflows.
Reproduction steps:
  1. Assign an AnimatorController to the avatar’s Animator.
  2. In the AnimatorController, create an Animation that animates a property of any component.
  3. Open the SDK Builder panel.
  4. In the Inspector, change the property that is being animated.
  5. After about 2 seconds, the value reverts to its previous state.
Expected behavior:
Even when the SDK Builder panel is open, the properties set in the Inspector should not revert.
A reproduction video using the VRC Position Constraint component is attached.