Screentime Application limits not working correctly

Hi - I am having an issue with the Screentime application limits on my kids ipad. They are expiring at half the time they are set for. i.e. if screentime limit is set for an hour, it expires at 30 minutes of use. I have tried deleting and redoing the limits with the same result. FWIW, my other kid's ipad screentime limits are set up the exact same way and are functioning properly. Help Please!