I was having this same issue of the cadence sensor always reading low and in the 60s. I haven’t done a ride but just got it to appear to read correctly for the first time ever. I did this by pairing/finding the speed and cadence sensors separately.
I did this by spinning the wheel and letting the speed sensor and establish a connection.
I then spun the cranks backwards to wake the cadence sensor and let it establish a connection.
I then hopped on and took the bike for a short ride and the cadence was magically reading correct. I did this on two separate tests and the cadence appeared to finally read right both times.
Before I was just spinning the cranks which in kind spun the wheel and woke and paired both sensors at the same time. Doing it this was never got my cadence to read correctly.
Hopefully my results last for a full ride.