Changing color order in an Excel chart

Excel applies series colors in the order that the series were added to the chart. When you open the color picker, you can see the six accent colors of the theme. The first series that is added to the chart will get the Accent1 color, the second series the Accent2 color, etc.

Changing the order of the series in the legend will not affect the series color. Therefore, if the 2012 series was added after the 2016 series, it will not have the same color.

So, with the rogue chart, you need to edit each series and manually apply the theme colors in turn.