How common are BankId certificates with incorrect data?

[BobbyTable]

So we've encountered a BankID authentication attempt with incorrect birthday data. The birthdate is off-by-one day. So for example the date is 02-01-1970 when the actual persons date is 01-01-1970. I've inspected my own BankID certificate and can see that there is a birthday field present

1. I'm now assuming that the Bank has issued an incorrect BankID . Does this happen? Shall we expect to see more of this?

2. In the cases where this happens, we are discussing what the reason might be:
   Theory A) It's a range-issue, where we can expect the date to be somewhere close in time of the correct date (for example plus minus one day)
   Theory B) It's a fat-finger problem where one of the numbers are typed wrong. This would give all the numbers in the date the same probability of being wrong. So it could be the same day, but a decade apart in time.

   I see how this might not be an issue for whoever manages this repo and reads this issue - but would love your thoughts!