For anyone having any issues with changing the Water Mesh Override for Water Body Custom, changing the height of the actor’s spline seemed to fix all problems. After changing the water mesh, I noticed that objects would only begin to float while falling halfway through the mesh. If you move the camera inside the water mesh, you can see where the underwater post-process begins. Going to the WaterBodyCustom actor and doing “Select All Spline Points” and adjusting their Z location until the post-process starts just under the surface fixes objects that would fall through the mesh. Hope this helps someone.