Screen time limits not updating

For years I’ve used screen time, down time and app limits to manage my daughter’s use of her iPhone. This past month or so it seems to have gone haywire! All apps are blocked after a minute of use, regardless of how long I set the limit to. The only way to fix has been to turn it off completely - which isn’t safe!

has anyone found a work-around? No updates pending so it isn’t that.

is the only solution purchasing a different brand of phone?