" If both wrist-based heart rate and chest heart rate data are
available, your watch uses the chest heart rate data."
This is not correct. Only if exercise recorded will be the chest heart rate used.
If I do a bike ride, my chest heart rate is connected to Edge 530 and Forerunner 255 simultaneously.
I start recording on Edge 530. Every data correct on the Edge 530.
I would have on the Forerunner 255 as described in the manual,
" If both wrist-based heart rate and chest heart rate data are
available, your watch uses the chest heart rate data."
The Forerunner 255 records only the wrist-based heart rate. (without start a exercise). And this gives very bad data, since the optical heart rate sensor does not record respiratory during exercise.
If I only press on the Fr255 for example recording "indoor bike", will be the chest heart rate recorded on the Fr 255.(and correct respiratory data)