Parental control

For a week now my daughter's screen time has been showing gray (empty) bars (the apps, however, are still showing colored values). These gray bars are included in the total screen time, but do not represent an actively used app. It seems like there is something running in the background that counts towards screen time. How do I find out which app, or which process this is. I just want to see the real screen time and not the distorted data