Steps to reproduce:

1. When I use snmp command on CentOS to get the OID, the value returned is correct, 0. The command is: snmpget -v 3 -a SHA -A <password> -l authPriv -u <user> -x AES -X <password> 192.168.11.6 -On IF-MIB::ifHCOutOctets.2
2. Output: .1.3.6.1.2.1.31.1.1.1.10.2 = Counter64: 0
3. So, I create the host and add an item snmpv3 agent as below
4. Item is enabled and the ifHCOutOctets.2 is created too
5. Create the graph for the Gig1/0/2 In and Out
6. Unit is bps

Result:
I don't know why, but the graph is being populated. The switchport is administratively shutdown, no cable is connected. I expect no graph because the snmp command output is correct.

And now, the CentOS output:

Thanks in advance.