Projection matrices are not the same per eye. Prior to installing the Oculus XR plugin the E02 cell of the projection matrix of the right eye is 0.1470005f (positive value). After installing the Oculus XR plugin the right eye projection matrix E02 cell value is -0.1470005f(negative value) . The left eye should be negative and the right should be positive. This is for projection matrices.

If one creates a project with the Oculus XR plugin with 2 cameras with one camera set to target eye left and the other camera set to target eye right they will see double vision in the oculus rift headset. I narrowed this down the the incorrect value in the projection matrix. This is not observable if only one camera is used and the target eyes are set to both.