[Tested on iOS - Unity 2022.3.13, AR Foundation 5.1.1 & 5.1.0] Adding an ARAnchor to a GameObject which has an AREnvironmentProbe causes the position of the GameObject to change between the intended position and the world Vector3.zero position. This appears to occur when either the ARAnchor or AREnvironmentProbe is updated. In my scenario, I first Instantiate a GameObject which is being placed as a child of the XROrigin. Immediately, the AREnvironmentProbe is added to the GameObject. Later, once the user confirms the position of the GameObject, the ARAnchor is added. The position of the GameObject changes seemingly randomly between the world Vector3.zero and the expected position. [Edit] Also the orientation of the Transform changes between Quaternion.Identity and the expected orientation.