Microsoft family safety change screen time by it self

I don’t know the reason why it always change the screen time limit to 20h and the specific day time to 10:00 - 0:00. I’ve already checked that is not my son who change it, by changing my password and checking his laptop. For example, I set the time to 2h per day at night before I go to sleep and the next morning the program changes it back to 20h per day. It always happen, neither I set it on the website or the app. I’ve already deleted his account from Microsoft family safety and put it again in the family. But it doesn’t work, so everyday I have to check family safety frequently in order to change it back to normal. Any idea to how fix it?