@ScruffR @mdma @mhdevx
One of my students found out that the Tinker on the cloud main IDE page has the problem. As soon as I flash tinker from the Particle App then AnalogRead A0 works. Perhaps the Tinker that is set for the main cloud IDE page could be updated.
The issue is described here
The correct Tinker is located here
https://github.com/spark/firmware/blob/latest/user/src/application.cpp