Ahh I had this issue as well, was driving me crazy. Not sure what the answer is on that, spent a couple hours on it and gave up. We also were using a Sky with time cycle plugin (TOD) and some image effects so hard to say what causes it. Same deal for us as well, when looking down or at certain angles, when the camera turns there is a sweet spot where it jacks with the color of the water and lights it up like that. It also changes the color of the Caustics as well.