Hello Edson,
Adding to Robert's response, I have observed that historical exports are "more complete" than current/real-time. I think you might be getting partial results when you do the export for today and its not necessarily because you are hitting a limit.
It is not a direct reference, but below is the snippet regarding export differences in Workspace views. At this point, I am assuming the campaign exports are governed by the same behavior.

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Nico Feliciano
Genesys - Employees
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