Just as a side note, I have a mish mash of cadence sensors and speed sensors and HRMs on some of my bikes. Using the Wahoo app on an i-Phone almost always find that one of the inexpensive sensors will either not pair or will give intermittent data to the phone. I don't have this problem with my Wahoo sensors. The sensors that are giving my problems are the XBOSS and CooSpoo.

Pairing those sensors with my Garmin Edge 530 is easy and always works. I conclude that the app is the problem not the sensors.