I performed a test and it resulted in no errors, but when I ran the same file again live it produced errors.
Test uploads are able to check for issues within the file in comparison to the current state of the corresponding records in Luminate Online. Duplicate registrations, gifts, milestones etc. are unable to be flagged due to each row being checked individually and not compared against other rows in the file. The file should be checked for duplicates by confirming no repeat id's or emails are within the upload before performing a test.