Beddit 3 - Automatic Measurement

Hi, I have the latest version of the Beddit App and just received the new Beddit 3 Sensor from Apple (exchange program for the Beddit 2 sensor). My problem is the following. If I enable "automatic measurement" Beddit turns on monitoring OK when I go to bed, but it doesn't turn off when I get up the next morning, e.g. Beddit stays on. I have to manually go to settings and disable "automatic measurement" for Beddit to stop monitoring.

Is this a bug? Has anyone else got the same problem? Thanks.