Hmm… I wonder if we need to have the ec2_asg module to wait for the healthCheckGracePeriod to expire before checking the instance health (assuming that it is an ELB health check type). Even with a health check grace period of one, there is a chance that the instance can become healthy in that time. Can you please open a bug on github.com/ansible/ansible-modules-core to track this?
Thanks,
James