When the Line Graph displays files, it normally shows the files all connected together even though there may be gaps between each file.

To make the Line Graph show only the current graph:

Display a Recorder Page

On the Display Menu, Click Options.

Click "Single File View On Batch Pages", click OK.

Now the Line Graph will only show the currently running or the last batches to be run graph.
Thus when a new batch is started, the previous display will disappear, and the line graph will only show data relevant to the current batch.