I'm not aware of anyone who had a passport, was trying to renew it, and was then denied it. There may be cases, but I'm not aware of them.
We're generally finding it's with regard to people who are getting passports for the first time. They've never had a passport and are trying to furnish proof of citizenship--for example, a birth certificate, and they don't have it. It's when we go looking that we discover that they never had citizenship or they lost it because they failed to retain it.