Mail attribute/column in reports does not return data for all users

Mail attribute/column in reports does not return data for all users

I've tried a few different reports and for some reason some user's attributes come back as empty but when i look in ADSI i see the attributes are populated. This is happening on a few custom attributes i setup but also with the Mail attribute that's built into the reports. any idea on what could cause the reports to not fetch the data? this is not happening with all users, just a handful.The fields come back empty in the reports but when i check ADSI the attribute is populated. 

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