Help BIP Report not pulling correct info

Summary

We recently went Live with OLC. One of the reports we built is a BIP report with several parameters.

Content

Here is the WHERE Clause with parameters.

For some reason when entering DUE_DATE no results are returned.  If I enter a value on DUE_DATE_FROM and leave DUE_DATE blank, results are returned.  Any ideas how I could fix?  Thank you

  WHERE     d1.c18 = NVL (:p_display_name, d1.c18)

         AND d1.c9 IN (:p_course_name)

         AND NVL (d1.c16, '1') = NVL (:p_coordinator, NVL (d1.c16, '1'))

         AND d1.c2 IN (:p_completion_status)