OK it looks like the bug was fixed for the hvm:ebs-ssd (General Purpose SSD) AMI builds and not hvm:ebs (standard/magnetic EBS).
For example, in ubuntu-wily-15.10-amd64-server-20160105.1 for us-east-1:
* ami-bfb5ead5 ( hvm:ebs ) - FAILS * ami-15b7e87f ( hvm:ebs-ssd ) - WORKS
for enhanced networking instance launches.
OK it looks like the bug was fixed for the hvm:ebs-ssd (General Purpose SSD) AMI builds and not hvm:ebs (standard/magnetic EBS).
For example, in ubuntu- wily-15. 10-amd64- server- 20160105. 1 for us-east-1:
* ami-bfb5ead5 ( hvm:ebs ) - FAILS
* ami-15b7e87f ( hvm:ebs-ssd ) - WORKS
for enhanced networking instance launches.