They aren't duplicates, each one was a different job. I just found it strange that some were labeled as "renewed 24 minutes ago", "posted in 39 minutes" and "posted 10 minutes ago". What's the difference between "renewed" and "posted in"?
Renewed jobs are older jobs that the client wants to bump up to the top of the listing pool since they didn't find enough freelancers yet. I believe jobs are eligible for renewal 30 days after the original job listing was made.