Vertical lines on facetted histogram are not matching the facet

📊 Plotly Python
1

I am having this dataframe

import random
import pandas as pd
random.seed(42)

so = pd.DataFrame({'x': random.sample(range(1, 100), 40),
                    'group': ['a']*10+['b']*10+['c']*10+['d']*10})

And I am calculating the percentiles:

so_percentiles = so.groupby('group')['x'].describe().reset_index()

which gives me:

group  count  mean        std  min    25%   50%    75%   max
0     a   10.0  41.2  33.773099  4.0  15.75  30.5  70.50  95.0
1     b   10.0  52.6  32.083918  5.0  28.50  60.0  74.50  97.0
2     c   10.0  65.1  31.067847  1.0  55.00  75.0  87.75  96.0
3     d   10.0  48.1  31.014154  7.0  21.25  46.5  68.75  99.0

I want to plot a histogram of x facetted by group and for each group plot a vertical line for the 25% and 75% percentile.

So I am using the following code:

import plotly.express as px

fig_so = px.histogram(so, x='x', facet_row='group', cumulative=False, histnorm='percent',
                   nbins=100,
                  category_orders={
                      'cluster': ['a','b','c','d']
                  })

for r, g in enumerate(['a','b','c','d']):
    
    val_25 = so_percentiles.query('group == @g')['25%'].values[0]
    val_75 = so_percentiles.query('group == @g')['75%'].values[0]
    
    fig_so.add_vline(x=val_25, line_dash="dot", row=r, col="all",
                  annotation_text="25th percentile", 
              annotation_position="bottom left"
             )
    fig_so.add_vline(x=val_75, line_dash="dot", row=r, col="all",
                  annotation_text="75th percentile", 
              annotation_position="bottom right"
             )

fig_so.for_each_annotation(lambda a: a.update(text=a.text.split("=")[-1]))
fig_so.update_yaxes(matches=None)
fig_so.show()

Though this outputs:

image

It seems that the vertical lines are not correctly matched to each group, since at the plot the 25th percentile for group d is around 28 whereas it should be 21.25.

I am using plotly version 5.5.0

Any idea why this is happening ?