How/where are you searching? In Endnote or from Word’s “find citation”? i tested as many ways as I could, and pulled the record I had modified in each instance.
Search on all fields should find it, or searching just the Research notes should find it. Also “find citation” from word’s endnote toolbar will find it (but there you cannot specify which fields to search, it will search all fields).
I tested this in Word 2016, Endnote X7.7.