Times in email notifications always in UTC

I’ve just installed Passbolt using the Docker containers. I’ve updated passbolt.env and mysql.env to match our server configuration and everything seems to be working. Notification emails are sent, users can activate caaounts, and passwords can be shared through the browser extensions

However, the notification emails always include the UTC time. I have update the TZ environment variable and verified that the containers have the correct timezone set with
docker exec -i bash -c 'date’

Nevertheless, the emails still arrive with UTC times. I don’t see any relevant environment variables in the reference list

Have I missed something?