Heart rate monitor measuring/reporting while I am not wearing the watch?

After a recent update, my instinct will frequently record a relatively high heart rate (anywhere between 90-140 BPM) while the watch is off my wrist prolonged periods of time. Wondering if anybody has had a similar experience. On version 7.20.

Edit: chiming in to say that, while toggling the heart rate sensor off and on seems to resolve the issue for a time, the HRM ultimately goes back to measuring phantom heartbeats. I would consider this an ongoing software issue.