The left and right rendered images are identical in the DigitalEyeware sample. This appears to come down to the fact that getEyeDisplayAdjustmentMatrix returns an identity matrix for the left and right eyes rather than something that offsets either view.
I'm running on a Pixel 1 with Android 9.0. The sample appears to be using "VR ONE" as the selected viewer, which does appear to have eye separation properies.
The screenshot below should have parallax, particularly where the tip of the spout is: