Callback with multiple outputs after page refreshed

Dash Python
1

Hi
I noticed that the function of the callback isn’t called after page refreshed if there are multiple outputs.
I mean, if I have the callback:

@app.callback(Output('dropdown', 'options'),
             [Input('button', 'n_clicks')])
def machines_select_all(select_all):
    # some functions

    return options

it will be called every refreshing the page.
And the next callback would be triggered only by the clicking of the button:

@app.callback([Output('dropdown', 'options'),
               Output('dropdown', 'value')],
             [Input('button', 'n_clicks')])
def machines_select_all(select_all):
    # some functions

    return options, value

Is it a bug or it should be so? I would like to trigger multiple output callback after page refreshing.