Screen Time Block not working for TikTok

Tiktok is still available for my child to use after her time limit has been reached and while the phone is on downtime. Please tell me there is a way to fix this? I have tried all the suggestions I can find. I'm at a loss.

Additionally, how can you keep a child from removing and adding apps they have already had previously. Once my child's time is up, they can remove the app and reinstall it and the time starts over. I already have it set up to not be able to delete or add apps, but since they have already had it, it doesn't block that.