Administrators may notice that their servers (EC2 instances) from AWS autoscaling groups  (ASG) are missing from the compute instances section of the inventory page. This is expected behavior, Vanta lists the auto-scaling groups the instances belong too in the Autoscale section of the inventory page:

Where administrators can click the purple instance link:

To view the instances in that autoscaling group:

This also means on the vulnerability page, vulnerabilities are shown for the autoscaling group rather than the individual instances:

Administrators would need to update the image being used on the auto-scaling group, and that should resolve the vulnerabilities for the nodes when they get re-deployed again. 

If instances outside of auto-scaling groups are missing, please go through the steps in How to troubleshoot AWS resources not Appearing in Inventory to further troubleshoot.