How about seeing like a bank? From bank's point of view it could be either honest mistake or deliberate lie. And if person is lying and have been caught - they always say it was an honest mistake.

All the bank knows is that they tried to get to know someone as required and that person gave them bad info. This is either intentional or unintentional.

Now, they could go in for a high-touch customer care process, but that has drawbacks. It's expensive. Every person intentionally providing incorrect information is going to claim it's unintentional, meaning that this high-touch customer care process is going to have to double as a strong anti-fraud screening. From the bank's perspective, this is failure-prone and needlessly risky.

If we're seeing like a customer, this is a shitty experience that they can't understand, negotiate, or do anything about. They're being punished and don't know why. If we're seeing like a bank, it's a way to control a risk for a known price.

Have you read the relevant KYC laws and regulations that the bank must follow? Otherwise how would you know this to be the case?