DuplicateCallbackOutput Error

I have built my dash app using flask as my main framework because i wanted to protect my dashboard views. The error i keep getting is the DuplicateCallbackOutput, everytime i reload my page.

#DASH APP
with flask_app.app_context():
#render dashboard template
dashboard_template = render_template(‘dashboard.html’,title=“Dashboard”)
dashboard_template = dashboard_template.replace(’{app_entry}’, ‘{%app_entry%}’)
dashboard_template = dashboard_template.replace(’{config}’, ‘{%config%}’)
dashboard_template = dashboard_template.replace(’{scripts}’, ‘{%scripts%}’)
dashboard_template = dashboard_template.replace(’{renderer}’, ‘{%renderer%}’)

#initialize dash_app
dash_app.index_string = dashboard_template
dash_app.config.supress_callback_exceptions = True

#Layout
dash_app.layout = html.Div()

#dash_app urls can be accessed once the user has logged in
dash_app = protect_views(flask_app, dash_app)

#DASHBOARD ROUTE
@flask_app.route(’/dashboard’)
@login_required
def dashboard():
vdata = VipimoData(current_user.token)

#validate token before proceeding
if not vdata.validate_token():
    return redirect(url_for('logout'))

#The rest of the steps is for validated tokens
get_locations = vdata.get_locations()

if 'success' in get_locations and len(get_locations['success']) > 0:
    locations = get_locations['success']

    nodes_per_location = {}
    for i in locations:
        if len(i['nodes']) > 0:
            nodes_per_location.update({i['name']:i['nodes']})

    locations_dropdown = [{'label':location, 'value':location} for location in nodes_per_location.keys()]

    #dash_app
    layout = Layout()
    dash_app.layout = layout.default(locations_dropdown)
"""
@dash_app.callback(
    Output('locations', 'value'),
    [Input('location', 'value')],
    [State('locations', 'value')]
)
def set_location(value, state ):
    print(value, state)
    return locations_dropdown[0]['value']"""

#cache
@cache.memoize()
def data_store(node, start_date=None, end_date=None):
    #get data
    node_data = vdata.get_data(node, start_date, end_date)

    #graph data
    graph_data = []

    if node_data.empty == False:
        columns = node_data.columns.tolist()
        new_columns = [ c for c in columns if c not in ['Timestamp', 'Coordinates', 'NodeID']]

        for c in new_columns:
            graph_data.append(go.Scatter(
                x=node_data['Timestamp'].tolist(),
                y=node_data[c].tolist(),
                name=c,
                line={'shape':'spline'}
            ))

    return graph_data

def generate_graph(node_name, graph_data):
    return {
        'data': graph_data,
        'layout': go.Layout(
             xaxis={'title':'Timestamp'},
             yaxis={'title':'Measurements'},
             title='Sensor - {0}'.format(node_name)
        )
    }

@dash_app.callback(
    Output('vipimo-graph', 'figure'),
    [Input('dstore', 'children')]
)
def update_graph(node):
    graph_data = data_store(node)

    if node and graph_data:
        return generate_graph(node, graph_data)



#return redirect('/dash-board')
return dash_app.index(current_user=current_user)