Ansible not becoming root when run from Bitbucket Pipeline – Ubuntu

I am running Packer + Ansible provisioner from the Bitbucket pipeline. but ansible not becoming root even become: true is given. Packer is used to create an Amazon Linux AMI and Ansible provisioner is used to run some server hardening scripts and configurations.

output from simple id command:
When run from Pipeline

TASK [aws-basic : debug] *****************************************
 ok: [default] => {
 "command_output.stdout_lines": [
     "uid=1000(ec2-user) gid=1000(ec2-user) groups=1000(ec2-user),4(adm),10(wheel),190(systemd-journal)"
  ]
}

When running from Locally

    TASK [aws-basic : debug] *****************************************
 ok: [default] => {
 "command_output.stdout_lines": [
     "uid=0(root) gid=0(root) groups=0(root)"
  ]
}

Following is my Ansible Playbook with two roles

- name: AWS EC2 AMLinux Configuration playbook
  hosts: default
  remote_user: ec2-user
  connection: ssh
  become: true


  vars:
    _date: "{{ansible_date_time.iso8601}}"
    reop_path: /usr/tmp/

  roles:
   - role: role-1
   - role: role-2

Packer ansible provisioner config

  provisioner "ansible" {
    playbook_file = "../ansible/aws-ec2-base.yml"

    extra_arguments = ["--extra-vars", "api_key=${var.api_key}"]
    galaxy_file     = "../ansible/requirements.yml"
    ansible_ssh_extra_args = ["-oHostKeyAlgorithms=+ssh-rsa -oPubkeyAcceptedKeyTypes=+ssh-rsa"]
  }

Even putting become_user: root in the ansible-playbook is not working.

Any reason this only happens in the bitbucket pipeline? I am using an ubuntu docker image with Ansible and Packer installed.