DView gap between stacked data sets with 2 graphs

If you have two stacked timeseries graphs with the same item selected in both, the position of this timeseries on the bottom graph mirrors the position on the top graph instead of laying on top of the bottom timeseries. As you can see in the image below, the blue data follows the shape of the dark green data on both the bottom and top graphs. Instead, it should lay directly on top of the pink data in the bottom graph.

Start by reproducing the issue in DView with two stacked time-series graphs and the same item selected in both. Trace the graph rendering or stacking entry point to determine why the lower graph reuses the upper graph's position; done means the series overlays the lower graph's corresponding data instead.