When PDNS is used as a slave to a server with WKS records, it incorrectly tries to insert a record in the database even though WKS records are not supported. This causes the SLAVE replication to fail and be re-tried over and over. If a record type is not supported, then we should drop it before hitting the DB.
Not a real fix, but in commit 566 we at least improve our error message. Silently dropping records is considered harmful.