I have been having a problem with my Garmin cadence sensor for a couple of weeks now - I think it started at about the same time as the last update. (Mac OS with an ANT±dongle)
Often, when I start riding, the cadence sensor shows really low values - it is connected, but the values are incorrect (always too low).
I have given the sensor a new battery, that didn’t help.
I can always solve the problem by going to the pairing-menu and unpair the sensor, then pair it again. Then it works fine for the rest of the session. But tomorrow, it will most likely do the same again.