Further testing clearly shows that the sensor is getting stuck and does not appear to be seated properly. The problem is most apparent when the composition adjustment is set to adjust the image composition rightward (sensor moves left when looking from the back of the camera; remember that the lens produces an inverted image) and the camera is oriented left-side up so that the SR system is moving against gravity (which should normally never cause a problem). The sensor began to shake in an attempt to move to the correct position which it could not. At times, the sensor stopped moving altogether and the SR system kept making a knocking noise, which meant that the sensor was locked up altogether. Occasionally, when trying to move the sensor a certain direction using composition adjustment, the sensor tilted instead of moving linearly as normally expected. Furthermore, the Dust Reduction function sometimes does not work (no sound from the DR II system is audible when the camera, only the aperture motor resetting; and selecting Dust Reduction from the menu exits immediately instead of taking about a second to complete). However, softly hitting the base of the camera body with lens facing up appears to clear up the problem.
From this information, it is clear that the sensor is not seated properly on the image plane, causing the SR mechanism to get stuck trying to shift the sensor to the correct position during operation. I will exchange the camera once B&H reopens.
--DragonLord