This issue drives me crazy.
I have an iPad and an iPhone, this issue never ever occurs on iPad, but will occur on iPhone every 6-7 days.
Remove the device from Devices and Simulators and re-add it does not work for me.
I don't know it the bug of Xcode or of iOS. If you check the Developer in Settings on iPhone, you will see it's missing.
That means that I need to reboot my iPhone every 6-7 days when it occurs.