Stacked barplot missing certain groups that have non-missing values in the data

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@jmaddalena is already working on this.

Since Jan 29, 2026.

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Description

P2

I have a very strange bug that I can't seem to diagnose.

Given the following data import:

plot_data = pd.read_csv("example_plot_data.csv")
plot_data['savedate_week'] = pd.to_datetime(plot_data['savedate_week'])

And the following basic plotly code:

import plotly.express as px

fig = px.bar(
        plot_data,
        x="savedate_week",
        y="commander_perc_of_card",
        color="commanders"
    )

fig.show()

Every week should have bars that total 100% and they do indeed in the data. They also do when you click on one of the commanders that has missing data. For example, when you click on Tiamat, the focused bar plot shows that it does have values for savedate_week = '2025-02-03'. And when you click on Ureni of the Unwritten, it has a value for savedate_week = '2025-06-16'. But both these values are missing from the overall stacked barplot.

I am using plotly version 6.2.0.

example_plot_data.csv

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