SingleLayerWater with PixelDepthOffset gives wrong refraction

We can see refraction gets distorted after we have a bigger PDO value, and it's not because the depth is more shallow, but looks like some kind of scene color texture lookup error.

Also, not sure if related, but instinctively PDO should be accounted for light transmission calculation. Currently it does not.

I've attached a uasset for ease of reproducing.

If reproduce manually:

1. Make a simple Single Layer Water material
2. Set refraction to 1.05
3. Set PixelDepthOffset to 0 
4. Apply it to a sphere or cube that sits on ground so we can see refraction. It appear correct
5. pump up the PixelDepthOffset