Polar HRM issues that I've seen are mostly two things: inadequate moisture under the electrodes or jersey material. Riding when cool or descending will often trigger 220 readings. Jersey flapping is the other main source. Some jerseys are worse than others. That's just static electricity. But 195 readings? I don't get those.
The computer software usually, but not always, discards anomolous readings. Check your downloaded data and see if it reflects these readings.