Where did the Configurations dropdown go in Workbench?

Recently I logged in to view add models to a partner space in preparation for an order. While browsing for my models I saw that the Configuration drop down, usually just above the upper left corner of the preview pane, was not available for some recently edited models. Older models with the Configuration dropdown still available were unable to preview older configurations.

We use configurations as a way of tracking revisions to a part, allowing us to roll back and fork from any configuration in the model. Currently I only have access the the last active Configuration of my models.

Is this a change in Workbench or an issue with my models?