have you every tryed to create a List of Dictionarys in Ansible?

For one of my projects, I need to create such a list. See the following two tasks:

- name: create List
  ansible.builtin.set_fact:
      LIST: [ {'size_gb': '{{ A[0] }}', 'type': 'eagerzeroedthick', 'autoselect_datastore': 'True'} ]
  delegate_to: localhost

- name: fill up the List
  ansible.builtin.set_fact:
      LIST: "{{ LIST + [ {'size_gb': '{{ item }}', 'type': 'eagerzeroedthick', 'autoselect_datastore': 'True'} ] }}"
  loop: "{{ A }}"
  when: A|length >= 2
  delegate_to: localhost

The problem, the secound task creates in the first run a dictionary, where the object {{ item }} is used as string instead of as placeholder. See following output:

TASK [create List] *********************************************************************************
task path: /ansible/playbooks.yml:81
ok: [CGN449 -> localhost] => {
    "ansible_facts": {
        "LIST": [
            {
                "autoselect_datastore": "True",
                "size_gb": "10",
                "type": "eagerzeroedthick"
            }
        ]
    },
    "changed": false
}

TASK [fill up the List] *********************************************************************************
task path: /ansible/playbooks.yml:86
ok: [CGN449-> localhost] => (item=10) => {
    "ansible_facts": {
        "LIST": [
            {
                "autoselect_datastore": "True",
                "size_gb": "10",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "{{ item }}",
                "type": "eagerzeroedthick"
            }
        ]
    },
    "ansible_loop_var": "item",
    "changed": false,
    "item": "10"
}
ok: [CGN449 -> localhost] => (item=20) => {
    "ansible_facts": {
        "LIST": [
            {
                "autoselect_datastore": "True",
                "size_gb": "10",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "20",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "{{ item }}",
                "type": "eagerzeroedthick"
            }
        ]
    },
    "ansible_loop_var": "item",
    "changed": false,
    "item": "20"
}
ok: [CGN449 -> localhost] => (item=30) => {
    "ansible_facts": {
        "LIST": [
            {
                "autoselect_datastore": "True",
                "size_gb": "10",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "20",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "30",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "{{ item }}",
                "type": "eagerzeroedthick"
            }
        ]
    },
    "ansible_loop_var": "item",
    "changed": false,
    "item": "30"
}
ok: [CGN449 -> localhost] => (item=40) => {
    "ansible_facts": {
        "LIST": [
            {
                "autoselect_datastore": "True",
                "size_gb": "10",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "20",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "30",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "40",
                "type": "eagerzeroedthick"
            },
            {
                "autoselect_datastore": "True",
                "size_gb": "{{ item }}",
                "type": "eagerzeroedthick"
            }
        ]
    },
    "ansible_loop_var": "item",
    "changed": false,
    "item": "40"

Actually, I use following Version:

ansible [core 2.16.3]
  config file = None
  configured module search path = ['/home/alphabeit/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3/dist-packages/ansible
  ansible collection location = /home/alphabeit/.ansible/collections:/usr/share/ansible/collections
  executable location = /usr/bin/ansible
  python version = 3.12.3 (main, Apr 10 2024, 05:33:47) [GCC 13.2.0] (/usr/bin/python3)
  jinja version = 3.1.2
  libyaml = True

So, why this happen? Does anyone have an idea and know how to fix it?

Best Regards
Alphabeit