In the current version of Forest Pro, a license is required to open any scene that includes Forest objects.
We are modifying the licensing system to do it less intrusive, so you can work with the scenes, requiring the license only to edit and render the Forest objects. These changes will be available in the next beta releases.
Until then, if you are using Network licenses and want to avoid that some workstations hold the available licenses, you can change the license mode of these computers from Network to Stand-alone.