The problem is the Sample Data can is installed while the SuiteCRM Wizard is passed. The Bitnami Docker Image for SuiteCRM has already passed the Wizard once it's started (it's passed during the initialisation of the Container).
In order to be able to start the Container with this Data installed, we need to add a parameter to the SuiteCRM Nami Module and adapt the logic to pass the Wizard using this parameter. Then you can pass this parameter with an environment variable when starting the containers.
Could you please open a issue on the GitHub repository requesting this feature?