FigureWidget does not recognize the datetime index passed to the x-axis.

Here's how to reproduce the issue:

Data:

dates = pd.date_range('2024', '2025', freq='QE')
df = pd.DataFrame([1,4,3,7], index = dates, columns=['val'])

Plot:

fig = go.FigureWidget(layout={'height':600, 'width':800})
fig.add_scatter(x=df.index, y=df.val)
fig

The values on the x-axis are mysterious.

Everything looks fine when I use go.Figure().

Python 3.12.9
Plotly 6.0.1
JupyterLab 4.4.4