IMDS v2 (Instance Metadata Service) introduced session authentication tokens which improve security when talking to IMDS. By default aws_instance resource sets IMDS session auth tokens to be optional. To fully protect IMDS you need to enable session tokens by using metadata_options block and its http_tokens variable set to required.
Instance metadata service can be interacted with freely
Follow the appropriate remediation steps below to resolve the issue.
Enable HTTP token requirement for IMDS