Formula returning a blank cell

I have been trying to figure this out for hours with no luck. We've created a formula to automatically update our status column in our project plan sheets. We have specific parent rows that are designated as milestones. The milestone row status cells should update based on the status of the child rows. A milestone row is indicated in the Milestone? row by clicking the symbol (star) to fill it in. I've got the formula below to guide automated status updates. In our milestone rows, the formula is returning a blank cell, and I cannot for the life of me figure out why. I've searched around in the Community and haven't seen a similar question/response. 

=IF([Milestone?]@row = 0, IF(Blocked@row = 1, "Blocked", IF(ISBLANK([Actual Start Date]@row), "Not Started", IF([Actual Completion Date]@row <> "", "Completed", IF([Projected End Date]@row < TODAY(), "Late", IF(NETWORKDAYS(TODAY(), [Projected End Date]@row) <= 2, "Deadline Approaching", IF([Actual Start Date]@row < TODAY(), "In Progress", "")))))) + IF([Milestone?]@row = 1, IF(COUNTIF(CHILDREN(), "Blocked") >= 1, "Blocked", IF(COUNTIF(CHILDREN(), "Late") > 1, "High Risk", IF(COUNTIF(CHILDREN(), "Deadline Approaching") >= COUNT(CHILDREN()) / 2, "Low Risk", IF(COUNTIF(CHILDREN(), "In Progress") > 0, "In Progress", IF(COUNTIF(CHILDREN(), "Complete") = COUNT(CHILDREN()), "Complete", "Not Started")))))))