Hey,
Me and my wife both have instinct solar watches and last night we observed something really strange.
Both hers and mine stopped measuring heart rate in the period of 1:28 AM - 2:28 AM exactly the same for both of us.
Is that due to an update being installed overnight and if yes how can we check it?
She had similar experience few days ago, but only happened to her watch, now its really strange how it happened to both of us in exactly the same period.
Some have theorized that the watch is looking for the Bluetooth connection and when it's not finding it, it's shutting down the other sensors to dedicate more power for Bluetooth. I don't know, it may just be a coincidence but other's have said they noticed this when the feature is enabled and the phone was out of range for that evening. Make sure the watch's Bluetooth is turned on and it's the phone that is disconnected. It'll be interesting to hear your findings.
No, it can't be that. I keep the bluetooth of my phone off and turn it on only for 15 minutes in the morning to sync (and sometimes, in the evening, too). I have never observed such behavior. All sensors appear to work throughout the entire night. And from what I see at the moment, my altimeter has not self calibrated in a while because it says I am 60 meters under the ground. 
