[1.16.1] Fabulous Graphics Doesn't Render Lines

[mrp_v2]

I have a mod that draws lines in the world, and everything works fine with Fast or Fancy graphics. However, with Fabulous graphics, no lines render at all. I've tried to look for the differences between Fabulous and Fancy graphics, but I can't find anything that looks useful. Anyone know why something that renders with Fancy graphics wouldn't render with Fabulous graphics?

Example code:

@SubscribeEvent
public static void renderEvent(RenderWorldLastEvent event) {
	@SuppressWarnings("resource")
	PlayerEntity player = Minecraft.getInstance().player;
  	Vector3d playerPos = player.getEyePosition(event.getPartialTicks());
  	//used to use lightning, but now uses a custom render type that is a mix of lightning and transparency
  	IVertexBuilder builder = Minecraft.getInstance().getRenderTypeBuffers().getBufferSource().getBuffer(RenderType.getLightning());
  	event.getMatrixStack().push();
  	event.getMatrixStack().translate(-playerPos.x, -playerPos.y, -playerPos.z);
  	Matrix4f matrix = event.getMatrixStack().getLast().getMatrix();
  	//example draw - makes a squre
  	builder.pos(matrix, 0, 70, 0).color(255, 255, 255, 255).endVertex();
  	builder.pos(matrix, 1, 70, 0).color(255, 255, 255, 255).endVertex();
  	builder.pos(matrix, 1, 70, 1).color(255, 255, 255, 255).endVertex();
  	builder.pos(matrix, 0, 70, 1).color(255, 255, 255, 255).endVertex();
  	//end draw
  	event.getMatrixStack().pop();
  	Minecraft.getInstance().getRenderTypeBuffers().getBufferSource().finish(RenderType.getLightning());
}