Several deliveries appear as 'to submit' in the tasks when duplicating a campaign

Hi,

I have been sending emails from ACC since November and I've realised that every time I duplicate a campaign, the previous deliveries are added to this duplicated campaign as 'Tasks' in the Dashboard and they appear with status = 'To submit'. 

They also appear in the deliveries folder with the pencil icon next to them, and there are several of them.

Is there a way I can get rid of these tasks? What do they exactly mean and why do they appear?

Thanks 🙂

Clara