We are working on stereo image of the inside pool and found out that the Caustic Photon Map as well as the Caustic Render Element are totally different comparing to the Default Vray Camera render without Stereo.
Could you please try to turn Direct visualization Off (from the Caustics options) for the Stereo renderings ? This should fix the missing caustics on the walls for the right view as well as the data in the Caustics render element.
Let me know if this helps or not.