ANSIBLE How to relative dict items to task results at loop

Need to register results from loop (task #1) and check when command.results stderr is not empty(task #2) relatively to loop items, so I can use this condition at new tasks.

The problem is that:

when condition from task #2 doesn't work cause I can't understand how to divide command.results relatively to loop items.

Is there solution to work around?

---
- name: "CHECK IF EXIST OPENVZ CONTAINER"
  hosts: "projectname-OPENVZHOSTS"
  gather_facts: yes
  remote_user: root
  vars:
    openvz_check:              "yes"
    openvz_instances:
      opwnvz_instance_1:  
        vmid:                  "119"
      opwnvz_instance_2:  
        vmid:                  "118"

  tasks:

  - name: "Ping my hosts"
    ping:


  - name: "1. Register exist containers"
    shell: echo $(vzlist -a {{ item.value.vmid }})
    register: command
    when: openvz_check == "yes"
    loop: "{{ lookup('dict', openvz_instances) }}"
    ignore_errors: yes

  - name: "2. Create variable from command"
    debug: msg="{{ command.results | map(attribute='stderr_lines') | list  }}"
    when: 
      - openvz_check == "yes" 
      - command.results | map(attribute='stderr') | list != "" 
    loop: "{{ lookup('dict', openvz_instances) }}"
    ignore_errors: yes

  - debug: msg="{{ command.results | map(attribute='stderr_lines') |list  }}"

Debug of command.results | map(attribute='stderr') | list:

ok: [projectname-OPENVZHOST-S1] => {
    "msg": [
        [], 
        []
    ]
}

Please get advice or solution as you see. Or what I need to research.

Regards

PS: have an idea to create folder and then check if it exist or not exist, but have no idea how to relation dict to results