Thank you for posting.
I am unable to replicate the issue you describe.
I have created the database file in FileMaker Pro 11v4 just as your screenshot shows. When I cut and paste "script 1" to "script 2" it does copy the script exactly and when it is run, the "group by" remains the same: (Field 2). The data exported when either script is run is the same. How does your output file differ?
Any additional details you can provide may help me in replicating your issue.