Grey column in screen time

On my screen time for the day it says I have been on my phone for 1h 45min when I’ve only been on it for 39 minutes. I have seen other posts about this topic and people say that the grey is the “other” categories if that were correct my other categories column should only be one minute so why is it at 1h 4min? Is it something in the background? It also said the other day that my first pickup was at 12:00 but it wasn’t till after 6:00am. What is the problem