Re: startup race leading to NOT IMPL on AXFR?

[ Quoting <[email protected]> in "Re: [nsd-users] startup race leadin..." ]
>> [2017-03-09 02:46:57.649] nsd[1692]: error: xfrd: zone
>> testdns.exim.org received error code NOT IMPL from [hidden-master]
>
>This might be a red herring. NSD as a slave tries IXFR first. However,
>the master is also NSD, and it cannot provide IXFR (because it doesn't
>have any journals), so it returns NOTIMPL. The slave then falls back to
>AXFR. If you want to avoid the initial IXFR (because it will never
>work), set this on the slave:

NOTIMPL when doing an IXFR? I thought the proper reponse was just to send
an AXFR at that point. At least RFC 1995 Section 4 says this. Has this been
updated by a more recent doc?