The credit bureaus do not always have a full DOB on their files.  In this case, our system will default it as follows:

If the credit bureau only has the YOB on file, our system will default that to 1/1/xxxx - therefore if the report reflects 1/1 and the year matches your applicant, the credit bureau only has the YOB on file.

If the credit bureau has the month and year on file, our system will default that to xx/1/xxxx - therefore if the report reflects xx/1/xxxx and the year and month matches your applicant, the credit bureau only has the month and year on file.

If the month or year do not match, then there is a likelihood that the credit bureau either has provided us with a wrong file, the credit bureau has the wrong DOB on their files, or that the DOB was entered improperly when requesting the report.