`setVertexBuffer(slot, null)` is a no-op with the Vulkan rendering backend but clears the slot with the OpenGL one

On OpenGL, GlRenderPass.setVertexBuffer stores the argument unconditionally, so null empties the slot and the next draw fails the required-slot check in VertexArray.bind(). On Vulkan, VulkanRenderPass.setVertexBuffer only binds when the argument is non-null, so null does nothing and the slot silently keeps the previous draw's buffer. Since vertex data usually comes from the transient ring buffer, that stale binding may point at recycled memory, so the draw reads garbage with no error. The frontend only catches this under STRICT_VALIDATION (IS_RUNNING_IN_IDE), so in release builds OpenGL throws while Vulkan renders stale geometry.