Regardless of whether EyeGazeMode is set to Bone Rotation, FaceTracking, or Both, the EyeLook Tracking Keys continue to receive values even when eye/face tracking is unavailable or VRCFT/OSC is disabled. These values do not appear to come from OSC, but seem to be generated based on head movement.

When eye and face tracking are available, the EyeLook parameters receive OSC-based values, and eye movement works as expected.

For avatars that use bone rotation to control eye direction, this behavior does not seem to cause any obvious issues when tracking is unavailable. However, for avatars that use blend shapes created and assigned according to Unified Expressions to control eye direction, the eyes move unpredictably when eye and face tracking are unavailable. This happens when the eight parameters from EyeLookOutRight through EyeLookDownLeft are assigned to Tracking Keys.

According to the official documentation, gaze uses simulated eye movement when eye tracking is unavailable. Is this simulated movement also intended to drive the EyeLook Tracking Keys regardless of the EyeGazeMode setting? If so, is there a way to prevent it from interfering with blendshape-based eye movement when eye and face tracking are unavailable?