From our first use of the Xbox One S we noticed that this console's fan does make a ticking noise. We noticed the same type of noise with the original Xbox One.
After hearing about more people being worried about the ticking noise that this newest Xbox creates we disasseble the console and take the entire fan apart to show the insides.
After looking at the fan motor, bearings and spring we found nothing to suggest that the ticking noise is something to be worried about. We've found that the fan is working as it should and there are no problems with it.
APKJunky