Updating the network interfaces triggers a validation to check for misconfiguration and errors.

Howto reproduce:

• add an interface with the same mac, ip, fqdn as another interface (say eth1), name it eth2
• remove eth1
• submit

Validation fails, explaining that eth1 and eth2 are conflicting (but eth1 should have been removed!)

Another example: try to migrate your primary, provisioning eth0 interface as a bond0

• add bond0 with the same mac, ip, fqdn as bond0
• activate provision and primary for bond0
• eth0 can now be deleted. remove eth0
• submit

I think this is related to #11031