ELB is now ipv6, how to check ipv4 and ipv6 connection and if I am still paying ipv4 addresses?

Checklist

• My website DNS dns has a CNAME record pointing to cloud front distribution
• the cloud front distribution has as my application load balancer as origin
• MY EC2 Load balancer is dualstack. It uses 3 dualstack subnets, once for availability zone of my region
• The task (a webserver) running as FARGATE SPOT instance is running
• website is reachable, both in http and https, when opened by browser using registered domain name

So 'it works'.

But ... is that enough or there is something other to configure for ipv6 transition? (I know, actually EC2 LB cannot be run as ipv6 only, strange, but ... ok.... )

Is this enough to not pay any ipv4 to amazon? Where can I check there is no public ipv4 assigned to something?

If I enter the single task detail page, is still see a public ipv4 assigned. But why ?! My subnets are configured as is, in cloud formation

  DualStackSubnetA:
    Type: AWS::EC2::Subnet
    Properties:
      # load balancer cannot handle ipv6-only instances, so we use dual-stack subnet configuration
      CidrBlock: 10.0.3.0/24
      # Indicates whether instances launched in this subnet receive a public IPv4 address. The default value is false.
      MapPublicIpOnLaunch: false
      AssignIpv6AddressOnCreation: true
      Ipv6CidrBlock: !Sub
        - ${VpcPart}${SubnetPart}
        - SubnetPart: 00::/64
          VpcPart: !Select
            - 0
            - !Split
              - 00::/56
              - !Select
                - 0
                - !GetAtt VPC.Ipv6CidrBlocks
      AvailabilityZone: !Select
        - 0
        - !GetAZs ""
      VpcId: !Ref VPC