Bar chart color will change if the size of data is huge

Hi Team,

I am using the bar chart and I found if the size of the data getting bigger, the color of the bar will get lighter even invisible.

Plotly: 4.5.0
JupyterLab: 1.2.6

import matplotlib.pyplot as plt
import plotly.graph_objs as go
from plotly.offline import init_notebook_mode
import plotly.offline as ply


x1 = list(range(1,100))
y1 = list(range(1,100))

fig = go.Figure(go.Bar(
        x = x1,
        y = y1,
        name = 'Long signal',
        marker = dict(color = 'red'),

After change 100 to 3000 the bar chart is getting lighter. Is this an issue or expected behavior? Thanks.