diff --git a/src/Http/Controllers/CP/Fieldtypes/ReplicatorSetController.php b/src/Http/Controllers/CP/Fieldtypes/ReplicatorSetController.php
index 6871fb8dd2..b4f4c56e70 100644
--- a/src/Http/Controllers/CP/Fieldtypes/ReplicatorSetController.php
+++ b/src/Http/Controllers/CP/Fieldtypes/ReplicatorSetController.php
@@ -11,6 +11,7 @@
 use Statamic\Fields\Field;
 use Statamic\Fields\Fields;
 use Statamic\Http\Controllers\CP\CpController;
+use Statamic\Support\Arr;
 
 class ReplicatorSetController extends CpController
 {
@@ -31,9 +32,7 @@ public function __invoke(Request $request)
 
         $field = $this->getReplicatorField($blueprint, $request->field);
 
-        $replicatorSet = collect($field->get('sets'))
-            ->flatMap(fn (array $setGroup) => $setGroup['sets'] ?? [])
-            ->get($request->set);
+        $replicatorSet = $this->flattenSets($field->get('sets'))[$request->set];
 
         if (! $replicatorSet) {
             throw new \Exception("Cannot find Replicator set [$request->set]");
@@ -76,9 +75,7 @@ private function getConfig(array $config, array $remainingFieldPathComponents):
         $isReplicator = isset($config['type']) && in_array($config['type'], ['bard', 'replicator']);
 
         if ($isReplicator) {
-            $flattenedSets = collect($config['sets'])
-                ->flatMap(fn (array $setGroup): array => $setGroup['sets'] ?? [])
-                ->all();
+            $flattenedSets = $this->flattenSets($config['sets'] ?? []);
 
             if (count($remainingFieldPathComponents) === 1) {
                 return $config;
@@ -104,6 +101,17 @@ private function getConfig(array $config, array $remainingFieldPathComponents):
         return $this->getConfig($fields[$remainingFieldPathComponents[0]]['field'], $remainingFieldPathComponents);
     }
 
+    private function flattenSets(array $sets): array
+    {
+        if (! Arr::has(Arr::first($sets), 'sets')) {
+            return $sets;
+        }
+
+        return collect($sets)
+            ->flatMap(fn (array $setGroup): array => $setGroup['sets'] ?? [])
+            ->all();
+    }
+
     private function resolveFields(array $fields): array
     {
         return collect($fields)
diff --git a/tests/Fieldtypes/ReplicatorTest.php b/tests/Fieldtypes/ReplicatorTest.php
index 5b62c44d19..7d2a2b097f 100644
--- a/tests/Fieldtypes/ReplicatorTest.php
+++ b/tests/Fieldtypes/ReplicatorTest.php
@@ -1105,6 +1105,58 @@ public function it_can_return_set_defaults_for_replicator_inside_grid()
         ], $response->json('new'));
     }
 
+    #[Test]
+    public function it_can_return_set_defaults_when_sets_are_stored_in_legacy_format()
+    {
+        $this->partialMock(RowId::class, function (MockInterface $mock) {
+            $mock->shouldReceive('generate')->andReturn('random-string-1', 'random-string-2');
+        });
+
+        $blueprint = Facades\Blueprint::make()->setHandle('default')->setNamespace('collections.pages');
+        $blueprint->setContents([
+            'sections' => [
+                'main' => [
+                    'fields' => [
+                        [
+                            'handle' => 'content',
+                            'field' => [
+                                'type' => 'replicator',
+                                'sets' => [
+                                    'video' => [
+                                        'fields' => [
+                                            ['handle' => 'video_url', 'field' => ['type' => 'text', 'default' => 'https://youtu.be/dQw4w9WgXcQ']],
+                                        ],
+                                    ],
+                                ],
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+        ]);
+
+        Facades\Blueprint::partialMock();
+        Facades\Blueprint::shouldReceive('find')->with('collections.pages.default')->andReturn($blueprint);
+
+        $response = $this
+            ->actingAs(tap(Facades\User::make()->makeSuper())->save())
+            ->postJson(cp_route('replicator-fieldtype.set'), [
+                'blueprint' => 'collections.pages.default',
+                'field' => 'content',
+                'set' => 'video',
+            ])
+            ->assertOk();
+
+        $this->assertEquals([
+            'video_url' => 'https://youtu.be/dQw4w9WgXcQ',
+        ], $response->json('defaults'));
+
+        $this->assertEquals([
+            '_' => '_',
+            'video_url' => null,
+        ], $response->json('new'));
+    }
+
     public static function groupedSetsProvider()
     {
         return [