The same results are given when tested against: pdns-server (3.4.1-4+deb8u8)pdns-server (4.0.3-1~bpo8+1) pdns-server (4.0.3-1+deb9u2)
To get a clean slate on 4.0, you need to disable the packet cache. However, as Christian noted, the errors reported otherwise do not actually hurt production usage.
Kind regards, -- Peter van Dijk PowerDNS.COM BV - https://www.powerdns.com/
