diff --git a/src/Illuminate/Routing/ImplicitRouteBinding.php b/src/Illuminate/Routing/ImplicitRouteBinding.php
index 8d597559dda..4d75630a0ef 100644
--- a/src/Illuminate/Routing/ImplicitRouteBinding.php
+++ b/src/Illuminate/Routing/ImplicitRouteBinding.php
@@ -46,7 +46,7 @@ public static function resolveForRoute($container, $route)
                         ? 'resolveSoftDeletableRouteBinding'
                         : 'resolveRouteBinding';
 
-            if ($parent instanceof UrlRoutable && ($route->enforcesScopedBindings() || $route->bindingFieldFor($parameterName) !== null)) {
+            if ($parent instanceof UrlRoutable && ($route->enforcesScopedBindings() || array_key_exists($parameterName, $route->bindingFields()))) {
                 $childRouteBindingMethod = $route->allowsTrashedBindings() && in_array(SoftDeletes::class, class_uses_recursive($instance))
                             ? 'resolveSoftDeletableChildRouteBinding'
                             : 'resolveChildRouteBinding';
diff --git a/src/Illuminate/Routing/Route.php b/src/Illuminate/Routing/Route.php
index 25be726a1ba..941a1ff0b5d 100755
--- a/src/Illuminate/Routing/Route.php
+++ b/src/Illuminate/Routing/Route.php
@@ -535,9 +535,11 @@ public function signatureParameters($conditions = [])
      */
     public function bindingFieldFor($parameter)
     {
-        $fields = is_int($parameter) ? array_values($this->bindingFields) : $this->bindingFields;
+        if (is_int($parameter)) {
+            $parameter = $this->parameterNames()[$parameter];
+        }
 
-        return $fields[$parameter] ?? null;
+        return $this->bindingFields[$parameter] ?? null;
     }
 
     /**
diff --git a/src/Illuminate/Routing/RouteUri.php b/src/Illuminate/Routing/RouteUri.php
index 113612f932e..323717741e1 100644
--- a/src/Illuminate/Routing/RouteUri.php
+++ b/src/Illuminate/Routing/RouteUri.php
@@ -44,27 +44,19 @@ public static function parse($uri)
         $bindingFields = [];
 
         foreach ($matches[0] as $match) {
-            $parameter = trim($match, '{}?');
-
-            if (! str_contains($parameter, ':')) {
-                $bindingFields[$parameter] = null;
-
+            if (! str_contains($match, ':')) {
                 continue;
             }
 
-            $segments = explode(':', $parameter);
+            $segments = explode(':', trim($match, '{}?'));
 
             $bindingFields[$segments[0]] = $segments[1];
 
             $uri = str_contains($match, '?')
-                    ? str_replace($match, '{'.$segments[0].'?}', $uri)
-                    : str_replace($match, '{'.$segments[0].'}', $uri);
+                ? str_replace($match, '{'.$segments[0].'?}', $uri)
+                : str_replace($match, '{'.$segments[0].'}', $uri);
         }
 
-        $bindingFields = ! empty(array_filter($bindingFields))
-            ? $bindingFields
-            : [];
-
         return new static($uri, $bindingFields);
     }
 }
diff --git a/tests/Routing/RouteUriTest.php b/tests/Routing/RouteUriTest.php
index 3b0f7def220..f5790258dd3 100644
--- a/tests/Routing/RouteUriTest.php
+++ b/tests/Routing/RouteUriTest.php
@@ -51,27 +51,22 @@ public function uriProvider()
             [
                 '/foo/{bar}/baz/{qux:slug}',
                 '/foo/{bar}/baz/{qux}',
-                ['bar' => null, 'qux' => 'slug'],
+                ['qux' => 'slug'],
             ],
             [
                 '/foo/{bar}/baz/{qux:slug}',
                 '/foo/{bar}/baz/{qux}',
-                ['bar' => null, 'qux' => 'slug'],
-            ],
-            [
-                '/foo/{bar:slug}/baz/{qux}',
-                '/foo/{bar}/baz/{qux}',
-                ['bar' => 'slug', 'qux' => null],
+                ['qux' => 'slug'],
             ],
             [
                 '/foo/{bar}/baz/{qux:slug?}',
                 '/foo/{bar}/baz/{qux?}',
-                ['bar' => null, 'qux' => 'slug'],
+                ['qux' => 'slug'],
             ],
             [
                 '/foo/{bar}/baz/{qux:slug?}/{test:id?}',
                 '/foo/{bar}/baz/{qux?}/{test?}',
-                ['bar' => null, 'qux' => 'slug', 'test' => 'id'],
+                ['qux' => 'slug', 'test' => 'id'],
             ],
         ];
     }
diff --git a/tests/Routing/RoutingRouteTest.php b/tests/Routing/RoutingRouteTest.php
index 00c42519f6d..c11843d44e0 100644
--- a/tests/Routing/RoutingRouteTest.php
+++ b/tests/Routing/RoutingRouteTest.php
@@ -1706,6 +1706,23 @@ public function testParentChildImplicitBindingsWhereOnlySomeParametersAreScoped(
         $this->assertSame('2|another-test-slug|3', $router->dispatch(Request::create('foo/2/another-test-slug/3', 'GET'))->getContent());
     }
 
+    public function testApiResourceScopingWhenChildDoesNotBelongToParent()
+    {
+        ResourceRegistrar::singularParameters();
+        $router = $this->getRouter();
+        $router->apiResource(
+            'teams.users',
+            RouteTestNestedResourceControllerWithMissingUser::class,
+            ['only' => ['show']],
+        )
+            ->middleware(SubstituteBindings::class)
+            ->scoped();
+
+        $this->expectException(ModelNotFoundException::class);
+
+        $router->dispatch(Request::create('teams/1/users/2', 'GET'));
+    }
+
     public function testParentChildImplicitBindingsProperlyCamelCased()
     {
         $router = $this->getRouter();
@@ -2109,6 +2126,13 @@ public function show(RoutingTestUserModel $fooBar)
     }
 }
 
+class RouteTestNestedResourceControllerWithMissingUser extends Controller
+{
+    public function show(RoutingTestTeamWithoutUserModel $team, RoutingTestUserModel $user)
+    {
+    }
+}
+
 class RouteTestClosureMiddlewareController extends Controller
 {
     public function __construct()
@@ -2366,6 +2390,14 @@ public function firstOrFail()
     }
 }
 
+class RoutingTestTeamWithoutUserModel extends RoutingTestTeamModel
+{
+    public function users()
+    {
+        throw new ModelNotFoundException();
+    }
+}
+
 class ActionStub
 {
     public function __invoke()