I'm having a similar issue still. I have 3 kids, each having their own iPhone XR. We are set up on Family Sharing, and I'm the organizer. I was able to manage each of their Screentimes from my iPhone 7 until earlier this week. One of my kids figured out the password (Grrr!!). Ever since then, I've been unable to control his Screentime from my phone. I've changed the password on his phone directly, but it isn't sync'd with my phone. Do i need to do something different to "re sync"? The other issue is that he cannot "Send Request" for app installation or more screentime to me. It now seems like it can only be controlled on his own directly. My other two kids' phones are fine.