My HRM pro data showing on someone else's strava

Is this a known issue? My HR data is exactly the same as my running partners? This person has never connected to my HRM and it doesn't show as connected to their apple watch and yet my data is somehow being shared across so that our run HR data is the same. It began happening approximately 4 weeks ago and we had been running together prior to this with no occurrence of sharing.

I have a Garmin forerunner 935 and use the HRM pro

Running partner has an apple watch and is not wearing a HRM but has previously used a Polar chest strap.

I can see that my HRM pro is visible under the apple watch list of known Bluetooth devices but it is not showing as connected.