Extract is being received twice by 3rd party

Summary:

We have an employee data extract that is set to run hourly. We were informed by the 3rd party that there are certain extracts that are being received twice on their end, they have the same file name. One file contains data, one is blank. First file that is being received is blank, second file being received contains the data.

Extract is defined to be sent only one per hour. Would like to seek the help of the experts what could be causing the behavior.

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