Why zero deep sleep?

I’m getting unusual tracking results, and I’m not sure if it’s due to a bug, incorrect tracking settings or an actual problem I have.
Over the 17 days of using the app, it recorded 25-ish% of deep sleep on the first day, 10-15% about three times in the first week, and exactly 0% on all other days. I thought the problem was having a way too hot blanket (could explain the 10-15%), but I fixed it and am still getting zeroes.
I am using the phone’s accelerometer with medium movement, heart rate, and light sensitivity, low sound (noisy room), and high phone (I don’t sleepscroll, I think).
How can I tell if the data is correct, and what can I do if it’s not?

Hi @Doodlinka, could you please ideally use the Left ≡ menu → (?) Support → Report a bug, and send us your logs? I will check what the data set looks like.
Where is the phone during the sleep tracking?

The phone is the bed, right next to me. Will send a report tomorrow