How is Screen Time calculated? Why is the calculated time seemingly longer than time spent on iPhone? Under Screen Time, the report for the time spent on my phone is 1 hour 5 minutes.
However, when looking at all the apps used, the time spent on the phone adds up to about 28 minutes and not 1 hour 5 minutes.
Time spent on iPhone for the full day:

But looking at all apps, the time spent is about 28 minutes



How is Screen Time calculated?

Why is time spent on the iPhone calculated to  1 hour 5 minutes if time spent on all apps is really about 28 minutes?



Note:

I'm using ios v14. iPhone SE 1st Generation.
The iPhone is supervised, (but I don't see why that would matter).
Share Across Devices is enabled, however, I don't own or use any other apple devices besides this iPhone (seemingly this shouldn't either matter).
This is a bug on ios 14.
From an article on Medium.com:

...Turns out I’m not the only one seeing weird issues with screentime.
There doesn’t seem to be a correlation in regards to the iPhone model.
It also doesn’t seem to be a very common problem. However, others have
been reporting other odd screentime glitches. Some have reported their
screentime being inaccurately high with no app to blame. And others
are also reporting that their phone claims they’ve spent hours on
websites they’ve never visited.


My Screen Time claims that I was using my iPhone for 24Hours! (let's hope I wasn't...).

I have visited stackoverflow for about 1 minute, however, it's calculated as 24 hours.

Also, all apps were fully closed, no apps were running in the background.