Bar Chart Row Facets example renders with white lines over the bars

[adamerose]

The example titled "Bar Chart Row Facets" on the page below shows a bunch of white lines on the bars between each data point. I don't think it is supposed to look like this and haven't seen this on other bar chart examples.
https://plot.ly/python/facet-plots/#bar-chart-row-facets

[nicolaskruchten]

This is intentional: there are many small stacked bars being rendered, with thin white borders...