Flutter - A TextEditingController was used after being disposed - Provider - flutter

Question

I have a List of custom widgets that contain a TextFormField and use a TextEditingController which I initialize in the initState() function of the custom widget. I have wrapped the custom Widget in a Dismissible Widget to remove them from a list using the onDismissed function. This all looks like this:
#override
void initState() {
super.initState();
widget.nameController = TextEditingController(text: widget.initialName);
widget.amountController = TextEditingController(text: widget.initialAmount);
}
#override
void dispose() {
widget.nameController.dispose();
widget.amountController.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
CreateOrEditRecipe createOrEditRecipe =
Provider.of<CreateOrEditRecipe>(context);
return Dismissible(
key: Key(widget.id),
background: buildSwipeActionRight(),
direction: DismissDirection.endToStart,
onDismissed: (direction) {
createOrEditRecipe.removeIngredientCard(widget.id);
},
child: Container(
child: Row(
children: <Widget>[
SizedBox(
width: SizeConfig.blockSizeHorizontal * 60,
child: TextFormField(
controller: widget.nameController,
decoration: const InputDecoration(
labelText: "Foo",
labelStyle: TextStyle(fontSize: 12),
),
),
),
],
),
),
);
removeIngredientCard(String toRemove) {
_ingredientCards.removeWhere((element) => element.id == toRemove);
notifyListeners();
}
After removing the UI is updated using notifyListeners().
This removes the custom Widget from the list correctly and the UI updates correctly aswell, but if I now select the TextFormField of the last of the remaining widgets in the list, I get an error.
This error does not appear when I remove the last widget of the list and then try to select the TextFormField of the last widget of the remaining ones.
Any ideas where the problem might be?