What is the problem? Please be detailed.
Briefcase seems to append and duplicate records IF Export is repeated WITH a previously-exported CSV already present.
What ODK tool and version are you using? And on what device and operating system version?
Briefcase 1.8.0 (also1.4.9 and 1.6) on Win
What steps can we take to reproduce the problem?
Export. Inspect the CSV
Export again. Inspect the CSV. The exported CSV will now contain double the number of records.
What you have you tried to fix the problem?
Move exported CSV's to a separate work folder. If Exports are later re-done for any reason there is no file to be appended to.
Anything else we should know or have? If you have a test form or screenshots or logs, attach here.
This happens only if a previously-exported CSV is present. It's a minor issue. Small teams handling several, large, oft updated datasets may be at risk of occasionally producing end products with duplicate records.