SQL: CONTAINSTEXT and BY ITEM-Full-Text Index do not return results #3484

CREATE DOCUMENT TYPE doc;
CREATE PROPERTY doc.lst LIST OF MAP;
CREATE INDEX ON doc(`lst.txt` BY ITEM) FULL_TEXT;
INSERT INTO doc SET lst = [{"txt":"This is"},{"txt":"a test"}]

SELECT FROM doc WHERE lst.txt CONTAINSTEXT 'is' -- 0 results
SELECT FROM doc WHERE lst.txt CONTAINSTEXT 'IS' -- 0 results

CREATE DOCUMENT TYPE ctr;
CREATE PROPERTY ctr.txt STRING;
CREATE DOCUMENT TYPE doc;
CREATE PROPERTY doc.lst LIST OF ctr;
CREATE INDEX ON doc(`lst.txt` BY ITEM) FULL_TEXT;
INSERT INTO doc SET lst = [{"@type":"ctr","txt":"This is"},{"@type":"ctr","txt":"a test"}]