The documentation for the cloneCollection command tells users to use a namespace of a collection, however we just prepend the current database name to the string they input. This means that the cloneCollection command will try and clone the incorrect database name if they follow the docs and use a fully qualified namespace name.

For example: db.cloneCollection("localhost:27017", "test.some_collection") will try and clone the collection test.test.some_collection when it is run from test