Two pages appear in pdf output

[moonlighthalfwindow]

When I try to output a pdf, I find that as long as the height of the output image is greater than 414, the pdf file will be two pages.

1. height=414

import plotly.express as px
import plotly.graph_objects as go


df = px.data.iris()

fig = px.scatter(df, x="sepal_width", y="sepal_length", color="species",
            facet_col="species")
fig.show()
fig.write_image('iris_scatter.pdf', height=414)

2. height=415

import plotly.express as px
import plotly.graph_objects as go


df = px.data.iris()

fig = px.scatter(df, x="sepal_width", y="sepal_length", color="species",
            facet_col="species")
fig.show()
fig.write_image('iris_scatter.pdf', height=415)

Height 415 seems to break through some limitations that prevent the image from displaying on one page.