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Initial Layout fails to Load with "TypeError: Cannot read property `0` of undefined"

Hi all,
I am having problems with my application. Recently the app’s initial layout started failing to load without any error message in the logs. The only thing I have to go off of are the two error messages I get in Chrome’s developer pane:

react-dom@16.v1_8_0m1599659278.13.0.min.js:125 TypeError: Cannot read property '0' of undefined
    at e.getWeight (type.ts:15)
    at EdgeFactory.tsx:124
    at forEach.js:47
    at _checkForMethod.js:22
    at Object.t [as a] (_curry2.js:28)
    at e.value (EdgeFactory.tsx:124)
    at EdgeFactory.tsx:45
    at e.memoizedCreateEdges (memoizer.ts:7)
    at e.value (EdgeFactory.tsx:141)
    at i.tableFn (index.tsx:34)

dash_renderer.v1_8_0m1599659278.min.js:20 TypeError: Cannot read property '0' of undefined
    at e.getWeight (type.ts:15)
    at EdgeFactory.tsx:124
    at forEach.js:47
    at _checkForMethod.js:22
    at Object.t [as a] (_curry2.js:28)
    at e.value (EdgeFactory.tsx:124)
    at EdgeFactory.tsx:45
    at e.memoizedCreateEdges (memoizer.ts:7)
    at e.value (EdgeFactory.tsx:141)
    at i.tableFn (index.tsx:34)

Now, to be honest, seeing this I am not even able to tell where to start debugging as I don’t get any hints as to which element is undefined.
The only “hint” I have is that the two tabs I defined like so:

session_id = str(uuid.uuid4())

    layout = html.Div(
        [
            html.Div(session_id, id="session-id", style={"display": "none"}),
            intro_div,
            navbar,
            dbc.Tabs(
                id="sections",
                children=[
                    dbc.Tab(exec_dashboard, tab_id="exec", label="Executive View"),
                    dbc.Tab(body, tab_id="ddive", label="Deep Dive"),
                ],
            ),
        ]
    )

load fine (i.e. the user can choose either of them and thus trigger an update of the layout upon which it loads normally). The tabs however start out empty.

I know this is a really bad question - no reproducible example etc. - and I’m not looking for a complete answer, but any pointer into what might be the problem - or how I might be able to identify the problematic elements - is highly appreciated.

Thanks in advance

Hello!
Your code looks fine to me, but the problem might be with the children of your Tab elements? What are they and where are they defined?