Making a Copy of a Google Sheets Adds Multiple Data Series for Area Chart

[B R]

Hello! 

I have a tracker that I created in Google Sheets that I use for my team members. The tracker I created is the Master copy, and for each team member I make a copy for their personal performance stats. When I make a copy of the Master and enter data into the copy, it adds multiple cell references into the chart series so the charts look crazy and don't show the correct data. 

When I first make a copy and check the chart, it is referencing the correct cells. However, when I enter data in the cells the chart should be referencing, that is when it adds new cells into the series. It's getting frustrating to have to clear out the extra data series each week. 

Has anyone had this happen before? What did you do to fix it?