Problem: I sent out a campaign with 1 audience name however when i look at my past reports they have a new audience name that i used recently.
Reason: The reason this could be happening is because you are using the same campaign to send out to a different audience after you already sent it out with a previous audience. Each campaign is tied to a report. If you change the audience in the campaign then the report audience will also change for this campaign.
Solution: To avoid this happening there is a simple solution. Under messages you will see your original message with your original audience. Select the campaign and instead of editing the audience choose "COPY". This will make a duplicate message with a duplicate audience. However since you have not sent this new campaign it will not affect your already sent report. Next edit the message to select a new audience. Make sure you also update the "Reply To" and if you had any links in the campaign you will want to select "Tracking Urls" and save the urls again. After this choose save and then you are ready to schedule and send. The result being a new report with your new audience and your old report keeping the old audience as it was.
Benefit: The reason it is recommended to do this is for tracking your reporting later on. It will be easier to see which audience you in fact did send to the time you sent it.