[Podman] Trouble with Podman secrets with v 3.2

Hi, I have v3.2 podman installed, but am having difficulty with the new secrets --type=env. I create the secret ok as file, but podman secret create secret_name --env=true $env_name fails. When I create the secret as file, no matter whether it is JSON or simple variable='thing', when I create the container using the command Podman run -dit --secret=secret_name,type=env --name=container_name image_id and then exec into the running container with Podman exec -it container_name bash, there is no environment variable named secret_name. Am I missing something? Regards James