When exporting a task plan to Microsoft project (MSP) via the Clarity PPM MSP Interface, if it has any dependencies with another project, it will open both project plans. The second project opens with just the tasks that are external dependencies to the first project.
This is working by design. When you export a project from PPM to MSP that contains an interproject dependency, an excerpt project of the project plan that houses the dependent task is also exported. (It opens with just the tasks that have a dependency with the original project being opened)