Docker save on private registry saves port in repository

I am building a docker image from a Dockerfile that has a FROM <private_repository>. To do this I have the following pipeline:

resources:
- name: repo
  type: git
  source:
    uri: <repo>
    branch: {{git-branch}}
    private_key: {{private-github-key}}

- name: child
  type: docker-image
  source:
    repository: <docker-internal>:443/child
    username: {{docker-username}}
    password: {{docker-password}}

- name: base
  type: docker-image
  source:
    repository: <docker-internal>:443/base
    username: {{docker-username}}
    password: {{docker-password}}

jobs:
- name: build-image-from-base
  plan:
  - get: repo
  - get: base
    params:
      save: true
  - put: child
    params:
      build: repo/ci
      load_base: base

With a Dockerfile for child:

FROM <docker-internal>:443/base

# ...

Problem is that FROM image has to include port :443 which causes issue no basic auth credentials if you try to build the Dockerfile from outside of concourse. If I change to FROM <docker-internal>/base as normal, then error occurs in the pipeline: unauthorized: authentication required.

Is there a way I can configure my pipeline so that I can keep FROM <docker-internal>/base in my image? My concern is that my configuration of docker will be too coupled with concourse if I have to keep it as is.

Start with the pipeline configuration, the Dockerfile, and the docker-image resource behavior for the saved base image and registry authentication. Reproduce the difference between FROM <docker-internal>:443/base and FROM <docker-internal>/base; done means the pipeline can use the port-free image reference without breaking authentication outside Concourse.