Scattergl fill not shown when too many scattergl-traces in plot

[kvanderwijst]

A strange bug happens when adding more than 508 scattergl traces to a figure: the fill property is not shown anymore:

n=509

fig = go.Figure()
for i in range(n):
    fig.add_scattergl(
        x=[0,1], y=np.random.random(2), mode='lines',
        showlegend=False
    )
fig.add_scattergl(
    x=[0.1, 0.9, 0.9, 0.1],
    y=[0.2, 0.2, 1.2, 1.2],
    mode='lines', fill='toself', fillcolor='red'
)
fig.update_layout(hovermode='closest')

With n=509, the fill doesn't show (but the line of the trace does), with n=508, the fill shows up.