Left-mouse-double-click the plot, than reduce (ScottPlot.FormsPlot) formsPlot1.Height/Width so that actual plot (inner rectangle) has zero (or lower) height/width. This throws NullReferenceException:

System.NullReferenceException
HResult=0x80004003
Message=Object reference not set to an instance of an object.
Source=ScottPlot
StackTrace:
at ScottPlot.Renderable.Benchmark.Render(Settings settings)
at ScottPlot.Plot.RenderBitmap()
at ScottPlot.Plot.GetBitmap(Boolean renderFirst, Boolean lowQuality)
at ScottPlot.FormsPlot.Render(Boolean skipIfCurrentlyRendering, Boolean lowQuality, Boolean recalculateLayout, Boolean processEvents)
at ScottPlot.FormsPlot.PbPlot_SizeChanged(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnSizeChanged(EventArgs e)
at System.Windows.Forms.Control.UpdateBounds(Int32 x, Int32 y, Int32 width, Int32 height, Int32 clientWidth, Int32 clientHeight)
at System.Windows.Forms.Control.UpdateBounds()
at System.Windows.Forms.Control.WmWindowPosChanged(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

using System;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1() => InitializeComponent();
        private void Form1_Load(object sender, EventArgs e) => formsPlot1.Render();
        private void Form1_Click(object sender, EventArgs e) => formsPlot1.Height = 20;
    }
}

Adding data doesn't help. Double-clicking back and then resizing does not throw the exception.