Sleep tracking issues on Forerunner 955

Thanks for that. I checked the setting both on my phone and watch yesterday and both indicated that they were both at version 27.09. Last night still no sleep tracking and again today I have had 2 upgrades applied to the watch - again the version has not altered. I does not indicate that the upgrade has failed but the regularity of the upgrades seems to imply that it is not working properly and/or the upgrade is a bit rubbish.

You're not alone, same problem here

I also have the same issue, since late January : almost daily updates, and no heart rate detection at night. 
Reinstalling the software via the 8 light button press method has not solved the issue.
Does someone at Garmin know what is going on, and can they find a fix? Sleep tracking was for me an important part of my initial purchase decision.

I have the same issue. Even after resolving the version update (I did have the asterix after the version number but have now succesfully updated the watch) which did resolve the constant updates issue, the watch continues to fail to record sleep and heart rate data correctly. I agree that sleep tracking, but especially heart rate data during the night is an essential function which will likely force me to move to a different watch brand.