Any Game1.spriteBatch draw methods called from the PostRenderGuiEvent will not actually draw if the zoom is not 100%. It looks like the render target is being changed by the core game. I believe the timing of the event would need to be changed or if anyone figures out how to adjust the spriteBatch in order to draw to the screen on this event a known workaround would be great.

Oddly, this happened for me when I downloaded and used the 0.40.1.1 release, but was fixed when I downloaded it again I noted it was 0.40.1.1-3 and there was no longer a problem.