DISTINCT not consistently passed to Item_func_collect

CREATE TABLE simple_table ( running_number INTEGER NOT NULL AUTO_INCREMENT ,

geo GEOMETRY, PRIMARY KEY ( RUNNING_NUMBER));

INSERT INTO simple_table ( geo) VALUES

(ST_GEOMFROMTEXT('GEOMETRYCOLLECTION EMPTY')),

(ST_GEOMFROMTEXT('GEOMETRYCOLLECTION EMPTY'));

CREATE OR REPLACE VIEW mysqltest_tmp_v AS SELECT ST_ASTEXT(ST_COLLECT(DISTINCT geo) OVER( ORDER BY running_number ROWS BETWEEN 1 PRECEDING AND CURRENT ROW)) AS geocollect FROM simple_table;

SELECT ST_ASTEXT(ST_COLLECT(DISTINCT geo) OVER( ORDER BY running_number ROWS BETWEEN 1 PRECEDING AND CURRENT ROW)) AS geocollect FROM simple_table;