Please note that the abandoned calls displayed on top are for the queue. These are the calls that were not answered and the caller hanged up or the call left the queue, either to the destination if no answer or because the call was transferred outside the queue.
The abandoned call numbers next to the agents are produced when the agent actively rejects the call by hitting decline or because the user has set the extension to DND without logging out of the queue and the queue manager keeps polling the extension. This way the queue manager keeps polling the extension and since the extension is set to DND it keeps rejecting the call generating a large amount of abandoned calls.