Unexplained misfunction

Two nights in a row, when I wake up in the morning I see the app has shut itself off and did not measure my sleep. I am certain I start it right, follow instructions and put the device on the bed upside down, knowing that the screen will turn itself off. It worked fine before but I now find it unreliable. When it works, I like the resulting data and presentation and interaction with other azumio apps and apple watch.

Lost in your proximity about Sleep Time+ Cycle Alarm Timer, v3.9