After upgrading to aws provider 6.12.0, I started getting a deprecation warning from terraform.

╷
│ Warning: Argument is deprecated
│
│ with module.ec2["ems"].aws_instance.this[0],
│ on .terraform/modules/ec2/main.tf line 43, in resource "aws_instance" "this":
│ 43: resource "aws_instance" "this" {
│
│ network_interface is deprecated. To specify the primary network interface,
│ use primary_network_interface instead. To attach additional network
│ interfaces, use the aws_network_interface_attachment resource.
╵

It appears that starting with aws provider 6.10.0 that the aws_instance resource has deprecated the network_interface argument and replaced it primary_network_interface, which only supports a single interface, additional interfaces are to be created separately and attached using aws_network_interface_attachment.