nested UnnestScan gives wrong results when clause is present

INSERT INTO `default` ( KEY, VALUE ) VALUES( "id1A", { "type":"TYPEA", "subId":"id1", "valueA": [ { "cId" : "c1", "valueB": [ { "valueC": "testValueA" } ] }, { "cId" : "c2", "valueB": [ { "valueC": "testValueB" } ] } ] });

CREATE INDEX `ix20` ON `default` (

  ALL (ARRAY (

    ALL ( ARRAY var2.`valueC` FOR var2 IN var1.`valueB`

          END))

    FOR `var1` IN `valueA`

    WHEN `var1`.`cId` = "c1" END), `subId`)

WHERE `type` = "TYPEA";

SELECT var2.valueC FROM default AS a

UNNEST a.valueA var1

UNNEST var1.valueB var2

WHERE a.type = "TYPEA"

AND var1.cId = "c1"

AND var2.valueC = "testValueA"

LIMIT 1;