usmUser line not always created

[Rusty Haddock]

net-snmp version 5.7.3

Config'd for the following MIBs:
SNMP_MIB_MODULES_INCLUDED="\
disman/event \
disman/schedule \
host/hr_device \
host/hr_disk \
host/hr_filesys \
host/hr_network \
host/hr_partition \
host/hr_proc \
host/hr_storage \
host/hr_system \
if-mib \
mibII \
snmpv3mibs \
tcp-mib \
ucd_snmp \
udp-mib \
ucd-snmp/disk \
ucd-snmp/dlmod \
ucd-snmp/extensible \
ucd-snmp/loadave \
ucd-snmp/memory \
ucd-snmp/pass \
ucd-snmp/pass_persist \
ucd-snmp/proc \
util_funcs \
utilities/execute"

SNMP_MIB_MODULES_EXCLUDED="\
hardware \
host \
ieee802dot11 \
notification \
notification-log-mib \
target \
tunnel \
ucd-snmp/vmstat \
utilities "

Configure​d as such:
./configure $CONFIGURE_FLAGS \
--prefix=/usr \
--sysconfdir=/etc \
--enable-shared \
--disable-static \
--disable-manuals \
--disable-scripts \
--enable-mib-config-checking \
--enable-ipv6 \
--disable-embedded-perl \
--without-perl-modules \
--enable-mfd-rewrites \
--with-logfile=/var/log/snmpd.log \
--with-persistent-directory=/usr/lib/snmp \
--with-sys-contact=***@localhost \
--with-sys-location=Unknown \
--with-default-snmp-version="3" \
--disable-debugging \
--with-out-mib-modules="${SNMP_MIB_MODULES_EXCLUDED}" \
--with-mib-modules="${SNMP_MIB_MODULES_INCLUDED}" \
--with-out-transports="${SNMP_TRANSPORTS_EXCLUDED}" \
--with-transports="${SNMP_TRANSPORTS_INCLUDED}" \
--without-libwrap \
--without-rpm \
--with-nl \
--with-security-modules="usm"

I stop the snmpd daemon and make sure that it has stopped. Add the
appropriate createUser lines to my persistent file. These match what
the script net-snmp-create-v3-user puts out. Add my user/r[ow]user
lines to /usr/share/snmp/snmpd.conf (although, I get the same effects
if I keep them in /etc/snmp/snmpd.conf instead).

Afterwards, I start snmpd and view /usr/lib/snmp/snmpd.conf and my
createUser lines are gone but with no usmUser lines.

I rerun this whole procedure and poof! there are my usmUser lines.

Sometimes this happens but without the oldEngineId line at the bottom
of my persistent file, /usr/lib/snmp/snmpd.conf which causes my snmpbulkwalk
to return "snmpbulkwalk: Unknown engine ID".

I'm already MAD -- this is driving me further past that point.

Have I misconfigured something here??? FWIW, I'm running on OpenWRT r46566.

Hints greatly appreciated!!
Thanks,
-Rusty-