Lack of sleep score despite having sleep stages

[Fredt0]

I am on Fitbit since 2017. I have moved to a Sense 2 ten days ago. 
Today, for the first time, I faced a lack of sleep score despite having the full spectrum of sleep stages.
I went through the help, waited 2 hours, checked that I had the last firmware version, restarted my device and waited one additional hour. It still does not work.

Any clue on what is going on? 

[MissMyData]

I wonder if the issue is broader because there’s also another recent Sense 2 post on these Community forum pages which seems to be very similar? Perhaps worth checking it out. 

[Pvey · Accepted solution]

The same has happened for me. Full sleep stages appear, but no readiness or sleep score. I have noticed it happens after I charge my sense 2. The readiness and sleep score doesn’t register the first night after charging. But the nights after all is normal again. 

[Fredt0]

Thank you, it seems to make sense. It happened twice, the nights after I charged my device as long as I remember. 

[Pvey]

It must be some bug in the system when it is being charged. It seems that it’s memory is being reset or something and it calculates the hours you wear the fitbit from scratch after charging. I also notice that my ‘recent actions’ are erased on my sense 2 after each charge.
Really hope fitbit can fix this.