You are testing a database that stores customer information. During data integrity testing, you discover that some customer records have duplicate entries with slight variations in data. What type of data integrity issue is this?

In this scenario, the issue is related to domain integrity. Domain integrity ensures that all data entered into a specific column meets certain specified criteria, such as data type and range. Duplicate entries with slight variations indicate a lack of control over the allowable values within a column, thus violating the domain integrity constraint. This can lead to inconsistencies in the data stored in the database.