Deploy fails 'Property Environment contains duplicate values.'

I recently upgrade my rack from a September 2018 version. We had an environment variable, ‘SERVICE’ which worked fine until upgrading to 20190801142802 (ECS).

The deploy fails and (almost) immediately rolls back because the Tasks resource fails to update with the error: ‘Property Environment contains duplicate values.’.

I was able to change the environment variable to SERVICE_NAME and deploys are fine now. Is there a list of environment variables which are reserved by Convox? I assumed they would be prefixed by ‘CONVOX_’.

Thanks

you can check for your duplicate key in the cloud formation template for the service. I had this error and it was right there. GL!