Microsoft Active Directory paged result is returning less number of records than page size even though the server has more records

We have Microsoft Active Directory which has 1 million entries. We are using ldapjs node module paging search to retrieve entries from the Active Directory. As per our observation in some retrieve calls the results size returned is less than page size. For example if my page size is 100 and expecting to retrieve 100 results but it is not returning 100 results instead it is returning less number of records even though my active directory server has more than page size records available. 

This behavior is intermittent and not fixed. Please suggest if anyone facing same behavior while retrieving data from Active Directory.

Thanks in advance.