Each Japanese citizen has a “registration record.” Public officials occasionally make some gross mistakes. For example, a wrong letter was written for my sister’s name when her registration record was made. My biological father noticed this when he obtained his registration record for inheritance after my grandfather’s death. It took a while for correction.
A public official made yet worse mistake when my uncle was born. He was born on December 31. My grandparents went to the public office to make his registration record soon after he was born, but it was not made at all because the public official was drunk during the New Year. They noticed this after his sixth birthday because no notification was delivered before my uncle got into the elementary school.
There might be some errors in documents necessary to apply for a visa in Japan. If you notice that, please get it corrected before applying no matter how long it takes. The Immigration Bureau does not guarantee that they would accept a correction request once a document containing an error is submitted.