HRM pro not tracking activities

Hello,

I have been using a HRM pro+ for a few months now paired to my FENIX7 as the watch sensor doesn't work to well on my wrist (it severely underestimate my HR).

For the last few trainings, my watch doesn't use the HRM for heart rate tracking even though is indicated as connected on the watch. The activity recaps on the Garmin connect app do not indicate that my HRM was in use (as it used to before). I tried to manually connect the device in the watch menus yesterday but after a few minutes of running my watch lost track of my position and then seemed to switch back to wrist sensing. Garmin connect still didn't show the use of the HRM.

I tried turning the watch off and on, unpaired the device and paired again but it didn't work. I haven't tried changing the battery on the HRM yet but the app says it is at an "OK" level and it still shows as connected to the app.

The first fail came right after I connected my watch to Garmin express through my PC to update maps but it seems it also updated some firmware but I am not sure it comes from that.

Does anyone has any input that might help pls?