Description of problem:
Can't select synced content in hostgroup when adding OS

Version-Release number of selected component (if applicable):
Satellite 6.9

Steps to Reproduce:
1- Set up a new content view with Kickstart repo (for example rhel8.2)
2- Publish and promote CV
3- Added CV new Hostgroup.
4- Add new kickstart repos to the content view (for example rhel8.5)
5- Removed old repos (rhel8.2 kickstart)
6- Publish and promote
7- Attempt to update Hostgroup.
When you now select the now OS (RHEL8.5) the synced content can not be selected

Actual results:
Unable to select the synced content.
Synced can only be selected after saving the hostgroup without the selecting synced content.
Then going back into the hostgroup to then be able to select it.

Expected results:
Being able to select synced conntent.

Additional info: