Sunlight causes Sense and Sense 2 to not register heartrate properly or not at all

[Zyplexer]

I have a Sense 2 and I walk twice a day. On my early morning walk I am getting 31 Zone minutes and then my afternoon walk I was getting 0 zone minutes. I suspected with the brighter lightning from the sun this was affecting the readings so covered my fitbit with a band and sure enough I got correct readings. This has happened on my previous Sense as well. Is this a know issue with fitbits?

[LZeeW]

Hello @Zyplexer and welcome to the Community.  Your experience, with two different devices, is just about as weird as it gets.  Zone minutes are heart rate based.  Sunlight shouldn't affect your heart rate readings, unless you wear it too loose, maybe?

[Zyplexer]

Maybe? I could try tightening instead of covering.