1.7.3 - stub-zone public domain

[ѽ҉ᶬḳ℠]

Hi,

is stub-zone is only serving private domains but not public domains?

Running a local authoritative server for the public domain and having a
stub-zone set in unbound for that public domain I noticed that unbound
is not querying the local authoritative server for that public domain
but querying upstream resolvers instead, which serve either from their
cache or querying the local authoritative server eventually.

That seems sort of redundant traffic and increasing the response time
since that public domain could be resolved straight from the local local
authoritative server instead?