Don
It was sitting really nice, other than my suspicion that it was the mounting pillars of my water lock mounting kit that was taking the load. Any cooler with a backplate will stop the board warping.what is the CPU sitting like? I'm slightly worried that because you are applying the load directly onto the silicone die that it could damage it/warp the chip with too much pressure, also possibly cause it to curve so that the outer contacts wont be touching?
I will add that there is a real risk of breaking your CPU doing this and will definitely invalid the warranty and wreck its resale value.