I’m lost and confused. Long story short, we used to have a system on a bare metal DELL server. It’s been migrated to an VM long time ago. There used to be a serial number pooled via snmp and all was good. But after moving to an VM, I’ve removed the serial extend from snmpd.conf and… every time we hit a discovery, serial it’s reread or something. It’s just annoing and strage.
How to get rid of it? I don’t want to remove it from NMS and add again as I will loose history of this machine 
Now snmpd.conf on a server looks like this:
extend distro /etc/snmp/distro
extend hardware '/bin/cat /sys/devices/virtual/dmi/id/product_name'
extend manufacturer '/bin/cat /sys/devices/virtual/dmi/id/sys_vendor'
extend apache /usr/bin/sudo /etc/snmp/apache-stats.py
extend mailq /usr/bin/sudo /etc/snmp/postfix-queues
extend postfixdetailed /usr/bin/sudo /etc/snmp/postfixdetailed
extend postfix-queues /usr/bin/sudo /etc/snmp/postfix-queues
extend mysql /etc/snmp/mysql
extend fail2ban /etc/snmp/fail2ban -c
extend osupdate /etc/snmp/osupdate
direct me what to check and I can do some more digging but I don’t know where to start