Duplicate mentions occur when the same post matches keywords in your trackers (think of a tracker as a folder for simplicity). This is typically due to one of two reasons, and there are different solutions for each one.
Duplicates Across Different Trackers
If similar keywords under different trackers capture the same mention, then yes, you might receive duplicate mentions.
In this case, the system will count the same post as separate mentions under each keyword, even though it is the same content.
This is not a system error but a result of how tracking by multiple keywords works.
If you want to avoid this, you can remove overlapping keywords from the different trackers or move them to the same tracker.
Duplicates Within the Same Tracker
If you have similar keywords under the same tracker, you can avoid that by making sure the Setup option to “Avoid duplicates” is checked (which is the default setting) in the tracker settings.
For the above tracker, the option “avoid duplicate mentions” is active, which means that if we capture a mention from a profile or keyword they are monitoring in this tracker, we'll fetch it once.
Be aware that deleted mentions cannot be retrieved once removed.