NCM using wrong polling method

[Amogh_MoreNM]

We are using NCM 2020.2.1 HF2 in which two firewall devices are configured with SNMP v3 polling.

But still SIEM  has detected that NCM source IP  has used snmp v1 polling . What could be the Issue.  

Alternatively is there any workaround wherein we can disable snmp polling but still continue with backup jobs as that is most important. Because  when we unmanage the node., the backup jobs are also not executed.

[Amogh_MoreNM]

We found that there is a Nightly Inventory Job which is causing the snmp v1 and v2  hits on the target device

THough the device has been configured to poll with snmp v3  .

Any suggestion on which configuration could cause the snmp v1 and v2 hits or is it a default behaviour of the NIghtly Inventory job.