Grid not rendering when smart rendering [pic]

I have smart rendering on for 500 rows which loads, but when I scroll, some of it is blank, as if it didn’t render the 500. Here is a picture of the example. What could be wrong?

Add to the init of the grid ( after setSkin command )

grid.setAwaitedRowHeight(18); //18 - height of row in case of your custom skin

I have done this, and it does not change anything. I am likely going to switch away from this product.