Hello hac66,
Thanks for posting. I understand wanting to make sure your device is secured, and I'm happy to see if I can help. As I understand it, you weren't prompted to unlock your iPhone with a passcode twice recently. Is that correct?
Does this happen every time you restart, or is it working as expected since making this post?
Do you use Touch ID, or do you always use a passcode to unlock your device?
You mentioned your device was charging overnight; did you have any apps running, like audio or white noise apps?
Also, under Settings > Touch ID & Passcode, which option do you have selected under "Require Passcode?"
As a general step, it may help to update your device to iOS 13.4: How to back up your iPhone, iPad, and iPod touch and Update your iPhone, iPad, or iPod touch
Take care.