@ScottNZ 

The visibility of infrared light to the human eye isn't the reason for the reflections seen in the camera's image when it is placed behind glass. Infrared light consists of various wavelengths, some of which are invisible to us (e.g. 940 nm IR LED). However, infrared LEDs continue to emit this light. Consequently, when the camera is positioned behind a glass window, the infrared light is reflected, which can impact the quality of the camera's image.

  @ScottNZ 

Then there is no more night mode without the IR light. This is a physical phenomenon that cannot be avoided. If you need to use the infrared light for nighttime imaging, the infrared light must remain on.

If there is sufficient external light to illuminate the entire scene for the camera at night, you might consider setting the camera to day mode all the time.