On December 15th, 2017 the Google Analytics “Real Time” traffic tool is broken on the mobile app for iPhone and other iOS devices. Currently, the “Real Time” traffic is about 1/3 of the actual real time traffic. When clicking on “Home” within the app, you will get a much better picture of actual real time traffic. You can also check your real time traffic on desktop Google Analytics which should be accurate.
Google is definitely turning the knobs on their services right now. We believe there has been a December 2017 Google Algorithm Update and now Analytics on mobile devices is malfunctioning. Get it together Google.