I took a look at your test project and have found the problem. There is custom widget in your app that is called ‘LineChart’ that also comes with the D3 library, but a newer version of it, v4. My Gauge chart widget uses v3. These libraries are causing conflicts now in your app.
The custom LineChart widget is coming with v4 overwriting my v3 D3 version. This v4 D3 version does not have a specific function, namely d3.tween, that is used by my D3 Gauge Chart, hence the error is thrown. See also:
What should have happened I think is that when running ‘Check Widgets’ in the Tools section in the Modeler, or bundling widgets, Mendix Studio Pro should have spotted this, you have 2 different definitions of D3.
So this is not really due to one of the widgets. When you strip the LineChart, the widget will work again.
I see 3 options, the most favorable being on top:
It is hard for me to understand where it goes wrong. I have a test app in which many use cases -similar to yours as well- are working (and which I use as a regression test app).
Can you recreate this issue in a test app and invite me? Then I will solve it for you.
I just released a new version of the widget -Mendix 8 compliant- in the AppStore, version 1.4.0. In this version I use the same D3 library as Mendix uses (4.13.0), hence the widget should work now in all those cases!