Referring to this documentation:
While working on this ticket:
One of our TSEs discovered that the .cfg file format cannot handle complex data types, and some of Liferay's portal properties are string arrays:
Therefore, we will need to update the documentation to discuss the .config file format, similar to what's documented here:
We will also need to export files as .config whenever there are string arrays and avoid using the .cfg format except when we know for sure that all property values are simple.