The validator should check for multiple declarations of the same subnet under different shared-network-names. This can happen after f.e. renaming one shared-network-name to a new name and mistakenly applying a history command to the old name, causing the old name to be recreated alongside the new one.
rename shared-network-name test-pool to shared-network-name test-6pool set shared-network-name test-pool subnet 2001:db8::/64 commit