The issue is resolved, it was a mistake at my side. I missed to enable "App groups" for the intent extension. The app group id is used by my SQLite db manager, and some SQL queries were being executed when a user add a widget, and also when press edit, which to my surprise caused no issues at all while development, only popped up in release builds

I would also like to add that the comment from me, which mentions a possible resolution works in some devices and in some other, the same issue persists - the widget still shows some placeholder views, and the editing does not work.