librarian-puppet ignoring pinned puppetlabs-apt version

[juniorsysadmin]

With the following Puppetfile, librarian-puppet attempts to fetch the latest puppetlabs-apt version, and fails due to puppetlabs-stdlib 4.13.0 conflicting with 4.6.0

mod 'puppetlabs/stdlib',
  :git => 'https://github.com/puppetlabs/puppetlabs-stdlib.git',
  :ref => '4.6.0'
mod 'puppetlabs/puppetlabs-apt',
  :git => 'https://github.com/puppetlabs/puppetlabs-apt.git',
  :ref => '2.3.0'
mod 'ploperations/puppetlabs_apt',
    :git => 'https://github.com/puppetlabs-operations/puppet-puppetlabs_apt',
:ref => '028f2626668b1c69192d4813a301eb0fbce18d6c'

At first I thought the cause may have been triggered by unpinned version ranges in metadata.json, but this seems not be the case. Also, I have only seen this issue triggered so far with puppetlabs-apt