Find condition with collection and hash not working in zf2 with DoctrineMongoODMModule

Question

Using ZF2 DoctrineMongoODMModule

my condition is : workflow_settings.assignees.user_id = '50e6c53cf8ae035c1b000001' when insert data with collection property condition not working but if convert in to hash it start working

when insert data with hash property condition not working even if i convert in collection type

Json data

"workflow_settings": [
     {
       "to_company": "54b925f61ebe95e86c8b4567",
       "approved_status": "false",
       "status": "",
       "assignees": [
         {
           "user_id": "50e6c53cf8ae035c1b000001",
           "name": "Ravindra Chouhan",
           "email": "rchouhan@intellobuild.com",
           "status": "",
           "date": ""
        },
         {
           "user_id": "5264be641ebe951e118b4568",
           "name": "Jackub Joe",
           "email": "jackub@gmail.com",
           "status": "",
           "date": ""
        }
      ]
    }
}

Array

[workflow_settings] => Array
(
    [0] => Array
        (
            [to_company] => 54b925f61ebe95e86c8b4567
            [approved_status] => false
            [status] =>
            [assignees] => Array
                (
                    [0] => Array
                        (
                            [user_id] => 50e6c53cf8ae035c1b000001
                            [name] => Ravindra Chouhan
                            [email] => rchouhan@intellobuild.com
                            [status] =>
                            [date] =>
                        )

                    [1] => Array
                        (
                            [user_id] => 5264be641ebe951e118b4568
                            [name] => Jackub Joe
                            [email] => jackub@gmail.com
                            [status] =>
                            [date] =>
                        )

                )
        )
)