- I've had my current Forerunner 265s for little over a year now and it was the first watch I experienced this issue with (have previously had Vivoactive & Venu models without issue). I figured it had to be the HR sensor then because nothing else changed. I tried all the things that Garmin and other users suggest from keeping it clean and dry, trying a nylon strap, getting a battery port cover and the only thing that actually worked was to simply stop wearing it at night. It's been some months now that I haven't been wearing it at night, but put it on first thing in the morning again so still wear it for the majority of the day and I haven't had a single issue but just two nights of sleeping with it again and I immediately have an angry red wrist! It is a shame because I'm missing out on a lot of features that you get from wearing it at night but there doesn't seem to be an actual solution.
