Flutter: Provider and Cloud Firestore Firebase for a Product Favorite System not working

I'm trying to develop a Products Favorites system in Flutter with no results. I feel like I'm close to getting it but I'm struggling with some issues. Please does anyone what I'm doing wrong?

First of all, I have an array of ids with the liked products associated with the user. enter image description here

Secondly: this is my ProductService with the method check favorite().

class ProductService extends ChangeNotifier {
bool _isLiked = false;
bool get isLiked => _isLiked;
  set isLiked(bool value) {
    _isLiked = value;
    notifyListeners();
  }
Future<bool>? checkFavorite(String? uid, String? productId) async {
    final resp = await _firestore.collection('users').doc(uid).get();
    Map<String, dynamic> data = resp.data() as Map<String, dynamic>;
    var likedProducts = data['liked_products'] as List<dynamic>;
    likedProducts.contains(productId) ? _isLiked = true : _isLiked = false;
    return _isLiked;
  }

Then I have a HomeView where a grid of products is displayed like so:

return Bounce(
            duration: const Duration(milliseconds: 150),
            onPressed: () => Navigator.pushNamed(context, 'product',
                arguments: {
                  'product': productService.products[index],
                  'user': loggedInUser
                }),
            child: ProductCard(
              product: productService.products[index],
            ),
          );

The UI result looks like this: enter image description here As you can see the ProductScreen is a layout that receives the user data and the product data as arguments.

Finally, when I go to the product screen and I call the method I print the disliked value to see if it's working. The error that I get is that when I enter the first time the result is always false. Then I go back with the Navigator. pop method and try again. On this occasion, it works fine but the data keep persistent. So when I go back and try to check a non-liked product the result keeps true until the next time that I repeat the process.

This is my code in Product Screen and this is the log with the random results...

class ProductScreen extends StatelessWidget {
  const ProductScreen({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    final productService = Provider.of<ProductService>(context);

    final arguments = ModalRoute.of(context)!.settings.arguments as Map;

    final Product product = arguments["product"] as Product;
    final UserModel loggedInUser = arguments['user'] as UserModel;

    productService.getProductSeller(product.productSeller);

    productService.checkFavorite(loggedInUser.uid, product.productId);
    print(productService.isLiked);

enter image description here

The main file has all the providers created. I also tried to print the ids to see if I was missing something out but the info is correct. My feeling is like if like the query to the database was a little bit delayed and when it's done it keeps persistent for a while....