Third party apps broken by Screen Time?

I’ve used a couple of productivity apps that access screen time for many years but for the past week or so they’ve been constantly crashing when I try to start them. They will work for a while if I restart my phone but only for 20mins or so, even if I do nothing else with my phone. After this they crash if I try to open them or do anything if they are already open.

I’ve updated to iOS 16.6 and deleted and reinstalled the apps several times as well as turning Screen Time on and off with restarts in between.

I’ve tried downloading some other productivity apps and everything that needs to access screen time has the same issue.

I’ve also noticed that the ‘Apps that can access screen time’ section of Screen Time settings completely disappears from my settings about the same time as the apps stop working. If I restart then it’s back.

I’m not using Apple Screen time itself to restrict anything. I’m on an iPhone 12 Pro

Any ideas? Ironically my screen time is shooting up as I try and fix this! Thanks.