The error is due to conflict in fact parser that tries to create a new Opreatingsystem object with the same description/title as an existing one. This fails due to unique constraints on the mentioned fields.

Steps to Reproduce:

This is from memory, exact steps may be a bit different.

1. Create an OS with:

name: RedHat
    major: 9 (or whatever matches your host OS)
    minor: 7 (or whatever matches your host OS)
    description: RHEL 9.7
2. Ensure no OS exists with name RHEL & major 9 & minor 7
3. Run the installer on a RHEL 9.7 Satellite server