Is this even possible? High HR while not wearing

It can also happen when the watch is on a soft fabric surface, where the light can refract unpredictably. On a firm surface, it should turn off.

Well, the watch wasn't moving and it was on a hard non-reflective surface and I also use the night mode where it switched everything off so I guess this is another bug. I'll report to Garmin accordingly.

That watch is definitely not worn the way Garmin recommends to avoid erraric HR readings.

WHR can still be tricked into producing numbers if the light is not reflected back evenly as has been noted; one of the reasons why I can still get WHR when my watch is on the handlebars. You might want to check that WHR is turned off with your ‘night mode’ which I’m guessing is Battery Saver Mode unless you’ve created your own power mode.

It is strange though. I had FR935 for 3 year and never had this message.  

Now on the Fenix 6 pro I got it already 4 times in 7 months.

There must be something related to the sensor or the design/weight of the device. 

Maybe GARMIN can clear some doubts  

Ant/bt cardio band nearby? It happened to me, too. 232 bpm.. 

Happened to me twice now in last 10 days while I was wearing it as I typically do. Both times WHR was WAY too high for several minutes. Both times had to restart watch to clear it. Must be a bug.

6x running 8.10

I don't know. But I noticed that sometimes the sensor of the band even if not connected to the watch, creates these problems. Excuse my English

I repeat sometimes I was in bed almost to sleep. I had a Fc of 232 bpm. I had the cardio sensor ant/bt on the bedside table a couple of meters from me

no other sensors nearby

Hai provato hard reset?