To aid in the narrative generation process, the extension makes several assumptions about the data in the visualizations the narrative will accompany. These assumptions can be helpful to know when trying to troubleshoot narratives that seem incorrect.
For line charts, the extension assumes the series is continuous. This means that the extension assumes that the line chart is being used to measure the performance of metrics over time. Therefore, the extension will look to call out changes from one period to the next because it believes the order of those periods to matter.
For bar and column charts, the extension assumes the dimension to be non-continuous. It is expecting the chart is being used to measure the values of measures across certain categories. Even if the x-axis has a time measure on it, the narrative will still talk about the entities as if they are components of some greater whole.