Drupal packages always appearing in changes.json API

[drumm]

We are currently polling https://packagist.org/metadata/changes.json for changes to packages we are mirroring. The code for this is at https://gitlab.com/drupal-infrastructure/package-signing/packagist-signed/-/blob/main/bin/update-needed.php?ref_type=heads#L47-50

We are making requests approximately every 20 minutes like

https://packagist.org/metadata/changes.json?since=17320522510000
https://packagist.org/metadata/changes.json?since=17320540870000
https://packagist.org/metadata/changes.json?since=17320551340000
https://packagist.org/metadata/changes.json?since=17320569580000

Every time the response has updates for drupal/drupal drupal/core drupal/core-recommended

https://github.com/drupal/core-recommended for example is not updated that frequently. The last 2 webhooks sent from GitHub over 24 hours ago

I can’t think of anything else on our end that could be triggering these 3 packages to update so frequently. Updating our mirror every 20 minutes of these 3 packages is taking a decent amount of resources, that I’d like to reduce.

Is there anything we can do better for this situation, or is something about these 3 packages somehow looping eternally in Packagist.org internals?