A record query for own hostname

Salutations:
I am trying to understand why, and subsequently prevent, sendmail from
performing a A record query for its own fully qualified hostname.
This appears to be for every email it receives and possibly for every
email it sends.

Here are some highlights from the config that may be of interest

Cwlocalhost
Fw/etc/mail/local-host-names
DSmy_smart_host

local-host-names contains
short-hostname
FQ-hostname

no mailertable

Of course the /etc/hosts, /etc/resolv.conf, and /etc/nsswitch.conf are
set up appropriately.

Any insights would be appreciated.

Cheers,
Joshua