Housekeeping.php does not clean up ipv4/ipv6 entries for non-existing devices

I tried to clean up the SQL database with the housekeeping tool with parameter "-b" to cleanup all entries for non-existing devices and see that ipv4 and ipv6 addresses and their related networks are not getting cleaned up. Cleanup ist ipv4/ipv6_networks must be taken carefully, because network could exist on different valid devices.