Runtime disconnects in Google Colab when rendering Folium maps

Question

I'm creating a figure in Google Colaboratory with folium. But when I try to output the figure using display() the runtime disconnects even though the html file of the figure, which I save using map.save(filename), opens outside Colab fine when accessing it from my files.

This error also only occurs when I add a 2nd layer to my folium plot.

This is my code if it helps:

def MSOA_Overlay(df, style_function, highlight_function, name):
    """
    Makes plot of a clustering.
    """
    Plot = folium.features.GeoJson(
    df,
    name=name,
    style_function=style_function,
    highlight_function=highlight_function, 
    tooltip=folium.features.GeoJsonTooltip(
        fields=['msoa11nm','label','numneigh','gi','pop','pop_den'],
        aliases=['MSOA Name','Cluster Label','Number of Neighbors',
                 'Common Neighbors Proportion','Population',
                 'Population Density'],
        localize = True,
        style=("background-color: white; color: #333333; font-family: arial; font-size: 12px; padding: 10px;") 
    ))
    return Plot

#creates map
m1 = folium.Map([54.5,-3],zoom_start=6.8,min_zoom=6,tiles='cartodbpositron')

#titles
title_html = '''
             <h3 align="center" style="font-size:16px"><b>{}</b></h3>
             '''.format('Spatial Adjacency of MSOAs in Catchment Areas at Time %.4g.' %(time))   
gi_colormap.caption = "Proportion of Common Neighbors"
den_colormap.caption = "Log Population Density"

#sets style of Choropleth
gi_style_function = lambda x: {"weight":0.4,
                            "color":'black',
                            "opacity":1,
                            "fillColor":gi_colormap(x['properties']['gi']), 
                            'fillOpacity':0.65}

den_style_function = lambda x: {"weight":0.4,
                            "color":'black',
                            "opacity":1,
                            "fillColor":den_colormap(np.log(x['properties']['pop_den'])), 
                            'fillOpacity':0.65}

#sets style of highlight                            
highlight_function = lambda x: {'fillColor': '#000000', 
                                'color':'#000000', 
                                'fillOpacity': 0.50}


#makes Choropleth map
MSOA_Overlay(MSOA_stab_df,
        gi_style_function,
        highlight_function,
        'Proportion of Common Neighbors').add_to(m1)

#makes Choropleth map
MSOA_Overlay(MSOA_stab_df,
        den_style_function,
        highlight_function,
        'Population Density').add_to(m1)

#makes boundaries plot
Boundaries = folium.GeoJson(
    cluster_stab_df,
    name = 'Boundaries',
    style_function = lambda x: {
        'color': 'black',
        'weight': 3,
        "opacity":1,
        'fillOpacity': 0,
        'interactive':False
    })

Boundaries.add_to(m1)


#adds to plot
m1.get_root().html.add_child(folium.Element(title_html))

gi_colormap.add_to(m1)
den_colormap.add_to(m1)

folium.LayerControl(collapsed=False).add_to(m1)

for i, row in Pro.iterrows():
    marker = folium.CircleMarker(location = [row.geometry.y,row.geometry.x],
                                 radius=3,
                                 color='white', 
                                 popup=row['NAME']).add_to(m1)
    
    m1.keep_in_front(marker)
m1.save(root  + 'Plots/' + str(time) + '/MSOA_Choropleth.html')

display(m1)

I can add data and the code for the colormaps if that helps.