I found an AMI I had built from 1.1.8 back on July 7th. I can create functional 1.1.8 instances from that, so it looks to be something unique to 1.2.0, but I can't say for sure because I don't have a working way to build 1.1.8 AMIs currently. The 1.1.8 playbooks rely on modules that have been removed from Ansible, so I would have to rewrite them or downgrade my ansible install.

Also tried 1.2.0-rolling-201812080337. My best guess is that its not copying the SSH key into the system properly to allow the vyos user to login, as the system responds, accepts the username, rejects the key then disconnects with no further auth method.

I tried the build with 1.2.0-rc9 and rc10 with the same results. The instance boots up without issue, but rejects any login attempts with the SSH key the instance was launched with. The error it gets back suggests its not configured for key or password login, or any other method for some reason.