Deep sleep % algorithm change?

Since late March my deep sleep percentage has increases dramatically to be consistently around 90%, which I don’t believe is correct.

I use sonar to track sleep and have not changed where I put my phone or anything else in my sleeping scenario.

Has the algorithm.for calculating this changed? If so, why? It now seems to be much less sensitive and makes all tlmy sleep graphs very flat, unlike they used to be.

I.can upload a screenshot if you like.

Thanks, James

Maybe the microphones are dirty?
Did you do the sensor test in settings menue?

Did you change anything else in your bed?

Sorry for bad english.