If the Data Refresh includes new student users, and the data refresh processing date is after February 1st, those new users will receive the Incoming Student role (and their parents receive the Parent of Incoming Student role) because their first student enrollment record is created in the next school year and not the current school year.

For example:

Your School is marked for 15/16 School year as Current Year on 7/1/2016. If you complete the Data Refresh for Students on 7/1/2016, with your 15/16 School Year marked as Current Year, the “New” Students, are inserted with the Incoming Student role. Their first enrollment record is for the upcoming School Year 16/17.
Note: In the above scenario, once you mark your 16/17 School Year as the Current Year, you will need to Enroll your Incoming Students.

Your School has marked  for 16/17 School Year as Current year on 7/1/2016.  If you complete the Data Refresh for Students on 7/1/2016 withe the 16/17 School Year marked as the Current Year the “New” Students, are inserted with the Student role. Their first enrollment record is for  the current School Year 16/17.