UnnestScan on scalar values not generating proper spans

INSERT INTO default VALUES("01",{"ka1": [1,2,3,100,101], "ka2":[{"id":1},{"id":100}]});

CREATE INDEX ix1 ON default (ALL v FOR v IN ka1 END);

EXPLAIN SELECT v  FROM default d UNNEST d.ka1 AS v WHERE v = 100;

Span generated is v IS NOT MISSING; 

Following works. Because Unnest results as object  and where clause has fields.

CREATE INDEX ix2 ON default (ALL v1.id FOR v IN ka2 END);

EXPLAIN SELECT v1.id  FROM default d UNNEST d.ka2 AS v1 WHERE v1.id = 100;