During "dlv" system test setup, the "sed" regex used for mangling the DNSKEY RRset for the "druz" zone does not include the plus sign ("+"), which may:
cause the replacement to happen near the end of DNSKEY RDATA, which can cause the latter to become an invalid Base64 string,
prevent the replacement from being performed altogether.
Both cases prevent the "dlv" system test from behaving as intended and may trigger false positives. Add the missing character to the aforementioned regex to ensure the replacement is always performed on bytes 10-25 of DNSKEY RDATA.