This is the most common culprit. If two people edit the same file at the same time, or if you edit a file offline and then reconnect while another version exists, Dropbox saves both to prevent data loss. These usually have "Conflicted Copy" added to the filename.
“Your team is probably paying to store duplicate files in Dropbox without knowing it. Here’s a simple 4‑step cleanup workflow.” duplicate files in dropbox
A: Not fully automated, but it does flag some conflicts and offers “clean up” suggestions for some accounts. This is the most common culprit