[N1QL] Secondary index not being used with a particular adhoc query with parameters

This bug is found while verifying MB-24871.
Index created:
CREATE INDEX `def_name` ON `default`(`name`) WHERE (`job_title` = "Engineer")

curl command issued:
curl -v http://Administrator:password@172.23.107.182:8093/query/service -d 'statement=EXPLAIN SELECT * FROM `default` where job_title=$job_title and name=$name&$job_title="Engineer"&$name="id@mail.com"'

Above command should use def_name as suggested in the examples in MB-24871 but instead it uses primary scan.
Tried various combinations of back ticks on job_title as suggested by Bingjie but it still uses primary scan.
Tried the same through cbq, it works.