plotly 6.1.2.violinmode='group' does not work

[junjiecai]

(Environment):
Plotly Version: 6.1.2
Python Version: 3.13.2
Operating System: macOS (Seqonia 15.2)

When using the violinmode='group', it just behave like violinmode='overlay'

Code to reproduce, just use the grouped violin plot example from official documentation

mport plotly.graph_objects as go

import pandas as pd

df = pd.read_csv("https://raw.githubusercontent.com/plotly/datasets/master/violin_data.csv")

fig = go.Figure()

fig.add_trace(go.Violin(x=df['day'][ df['sex'] == 'Male' ],
                        y=df['total_bill'][ df['sex'] == 'Male' ],
                        legendgroup='M', scalegroup='M', name='M',
                        line_color='blue')
             )
fig.add_trace(go.Violin(x=df['day'][ df['sex'] == 'Female' ],
                        y=df['total_bill'][ df['sex'] == 'Female' ],
                        legendgroup='F', scalegroup='F', name='F',
                        line_color='orange')
             )

fig.update_traces(box_visible=True, meanline_visible=True)
fig.update_layout(violinmode='group')
fig.show()

Expected Behavior:

Actual Behavior:
In 6.1.2, "group" give the same result with "overlay"

Additional Notes:
After I downgrade to 6.0.1, the same code works fine