Setup: OS1 has a single associated media, Media1 and there is a Hostgroup1 associated with OS1 and Media1.

Re-create: Then change the associated media for OS1 to Media2, with Media1 no longer being associated with OS1.

Bug: If you now go to the hostgroup Operating Systems tab it lists the selected media as Media2.

Foreman is listing Media2 because it is the only valid option based on the selected OS1. But in reality on the backend the hostgroup is saved with Media1. It makes sense that the Hostgroup would not just be automatically updated with a new valid media selection but there should be some warning in the UI that the Hostroup now has an invalid selected media based on it's OS selection. The UI should definitely not show one media selected, since it is the only option, when in reality a different media is the one the hostgroup is saved with.