[BUG] Multi Page App - First Load Fails

[sjtrny]

Describe your context

dash==2.6.0

Describe the bug

First request made to a multi-page app fails. Refreshing the page resolves the issue.

Expected behaviour

First request should work.

Demo

dash_error.mp4

Code

import dash
from dash import Dash, html

app = Dash(__name__, use_pages=True, pages_folder='')

app.layout = dash.page_container

layout = html.Div(children=[
    html.H1(children='Hello Dash'),
])

dash.register_page("index", layout=layout, path="/", title="Index")

if __name__ == "__main__":
    app.run(host='0.0.0.0', debug=True)

[ned2]

I believe this is a known bug that was introduced by #2126 There's an open PR to revert the change that introduced the regression: #2168

[sjtrny]

Thanks @ned2!