I'm not sure. The design choice at that point was to avoid modifying any record sets and instead just "fail safely". Though maybe the main reason was that it was simpler to implement in our case if it should include avoiding this case of referrals to local IPs.Unfortunatelly it leads to a massive traffic amplification with real clients. Because of RCODE 5 they keeps retrying... I had to disable rebinding protection completely in order to make the network stable. Refusing them is not a good idea if you have a large deployment.
Either way, those delegations do seem in disarray. dig + trace also complains with lines like
;; BAD (HORIZONTAL) REFERRAL ;; communications error to 10.52.192.140#53: network unreachable
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