I noticed such issue with following AppRouter:

@AutoRouterConfig()
class AppRouter extends _$AppRouter {
  AppRouter({super.navigatorKey});

  @override
  List<AutoRoute> get routes => [
        AutoRoute(
          initial: true,
          page: SplashRoute.page,
        ),
        AutoRoute(
          page: MainRoute.page,
          children: [
            AutoRoute(
              initial: true,
              page: FirstRoute.page,
            ),
            AutoRoute(page: SecondRoute.page),
            AutoRoute(page: ThirdRoute.page),
          ],
        ),
        AutoRoute(page: FourthRoute.page),
    ];
    }

My navigation stack is:

=> FirstRoute

=> SecondRoute

=> FourthRoute

And when I tried popUntil to the FirstRoute, it’s not working.

What am I doing wrong? How to fix this?