Entity Culling does not call TileEntity#shouldRenderInPass(int) right before rendering the tile entity. Instead that method is called earlier for both rendering passes and the tile entity is added to up to 2 lists. Later on all tile entities in these lists will be rendered. Thus the BlockDualVertical.renderPass field is not set before rendering the tile entity. Can be fixed by calling MinecraftForgeClient#getRenderPass() to retrieve the current render pass when a tile entity is rendered.