Dash_table with debug mode throws error

I have a relatively simple dashtable that fails to load when I use debug option in running the server.
Literally I can can change the server launch from:
app.run_server(host=“0.0.0.0”)
to
app.run_server(host=“0.0.0.0”,debug=True)
And I start seeing “Invalid argument columns[0].id passed into DataTable”
The table without debug renders fine.
I’ve removed most of the dynamic data fetches and made it into a small static table and it shows the problem.
Any clues? what else should I be setting or doing for Debug mode?

import re
from datetime import datetime as dt

import dash
import dash_core_components as dcc
import dash_html_components as html
import dash_table
from dash.dependencies import Input, Output

app = dash.Dash(__name__)

app.layout = html.Div(
    children=[
        html.H1('Violation Viewer'),
        dcc.DatePickerSingle(
            id='my-date-picker-single',
            min_date_allowed=dt(2020, 4, 1),
            date=str(dt.today())
        ),
        html.Div(id='output-container-date-picker-single'),
        html.Div(
            style={"fond-family": "Arial"},
            children=
            [
                dcc.Loading(id="tbl-load",
                            children=[
                                dash_table.DataTable(
                                    id='violationtbl',
                                    data=[],
                                    sort_action='native',
                                    # fixed_rows={'headers': True},
                                    # style_table={'height': '500px', 'overflowY': 'auto'}
                                )
                            ]
                            )
            ]
        ),
    ]
)


@app.callback(
    [Output('output-container-date-picker-single', 'children'),
     Output('violationtbl', 'data'), Output('violationtbl', 'columns')],
    [Input('my-date-picker-single', 'date')])
def update_output(date):
    string_prefix = 'You have selected: '
    dateresponse = ""
    if date is not None:
        date = dt.strptime(re.split('T| ', date)[0], '%Y-%m-%d')
        date_string = date.strftime('%B %d, %Y')
        dateresponse = string_prefix + date_string

        cols = [{"id": 0, 'name': "url"},
                {"id": 1, "name": "analysis_test"},
                {"id": 2, "name": "analysis_baseline"}]
        data = [
            ['x', 'open', 'open'],
            ['y', 'test hello', 'closed'],
            ['z', 'open', 'http 200'],
            ['a', 'closed', '400'],
        ]
        return dateresponse, data, cols


server = app.server

if __name__ == '__main__':
    app.run_server(host="0.0.0.0")

Found another thread with similar issue.