I thought that safetyreportid is the unique identity of a report, but I found that some safetyreportid like "5390497-5" has two or three reports in openFDA when I search by API:
https://api.fda.gov/drug/event.json?search=safetyreportid:%225390497-5%22&limit=99
Could I ask why there are multiple reports with the same safetyreportid in openFDA?