The default configuration of snmpd on Debian has debug level logging enabled and thus we end up with a constant flood of these messages in /var/log/syslog

snmpd[19784]: error on subcontainer 'ia_addr' insert (-1)

The fix is to lower the logging level, which can be accomplished like this on systems with systemd:

cp /lib/systemd/system/snmpd.service /etc/systemd/system/snmpd.service
sed -i 's/Lsd/LS6d/' /etc/systemd/system/snmpd.service
systemctl daemon-reload
systemctl restart snmpd

On systems without systemd, the logging level is set by the init script (unless explicitly configured in /etc/default/snmpd), and can be changed like this:

sed -i 's/Lsd/LS6d/g' /etc/default/snmpd
sed -i 's/Lsd/LS6d/g' /etc/init.d/snmpd
service snmpd restart