Поправил логику обхода массивов.

добавил тесты

src/Dto2DataConverter.php

@@ -42,27 +42,12 @@ class Dto2DataConverter
 
             $value = $this->grabValue($object, $sourceName);
 
-            if (is_object($value)) {
+            // Если нет карты, то не сериализуем.
-                // Если у объекта нет карты, то не сериализуем.
+            if (is_object($value) && is_array($propertyInfo)) {
-                if (!is_array($propertyInfo)) {
-                    continue;
-                }
                 $value = $this->convertObjectByMap($value, $propertyInfo, $tags);
             } elseif (is_iterable($value)) {
-                $tempValue = [];
+                $map = is_array($propertyInfo) ? $propertyInfo : null;
-                foreach ($value as $item) {
+                $value = $this->convertArrayByMap($value, $map, $tags);
-                    if (is_scalar($item)) {
-                        $tempValue[] = $item;
-                        continue;
-                    }
-                    if (is_array($item)) {
-                        continue;
-                    }
-                    if (is_object($item)) {
-                        $tempValue[] = $this->convertObjectByMap($item, $propertyInfo, $tags);
-                    }
-                }
-                $value = $tempValue;
             } elseif (!is_scalar($value) && null !== $value) {
                 continue;
             }
@@ -77,6 +62,26 @@ class Dto2DataConverter
         return $data;
     }
 
+    public function convertArrayByMap($data, ?array $map, array $tags = []): ?array
+    {
+        $tempValue = [];
+        foreach ($data as $key => $item) {
+            if (is_scalar($item)) {
+                $tempValue[$key] = $item;
+                continue;
+            }
+            if (is_iterable($item) && $map) {
+                $tempValue[$key] = $this->convertArrayByMap($item, $map, $tags);
+                continue;
+            }
+            if (is_object($item) && $map) {
+                $tempValue[$key] = $this->convertObjectByMap($item, $map, $tags);
+                continue;
+            }
+        }
+        return $tempValue ?: null;
+    }
+
     protected function grabValue(object $object, $sourceName)
     {
         if (method_exists($object, $sourceName)) {

tests/unit/Converter/FillTest.php

@@ -43,6 +43,22 @@ class FillTest extends \Codeception\Test\Unit
             $author1,
             $author2
         ];
+        $helloRequest->authors2 = [
+            [
+                "name" => "Tolkien"
+            ],
+            [
+                "name" => "Sapkovsky"
+            ]
+        ];
+        $helloRequest->authors3 = [
+            [
+                "name" => "Tolkien"
+            ],
+            [
+                "name" => "Sapkovsky"
+            ]
+        ];
         $buy = new BuyRequest();
         $buy->phrase = 'Buy buy!!!';
         $buy->length = 10;
@@ -53,25 +69,41 @@ class FillTest extends \Codeception\Test\Unit
         $helloRequest->bar = $bar;
 
         $dto = $dto2DataConverter->convert($helloRequest);
+        // codecept_debug(json_encode($dto));
 
-//        $this->assertEquals('asdf', $dto->surname);
+        $this->assertEquals([
-//        $this->assertEquals(3, $dto->age);
+            "surname" => "asdf",
-//        $this->assertEquals([
+            "fake_age" => 3,
-//            'sfdgsa',
+            "emails" => [
-//            'af234f',
+                "sfdgsa",
-//            'asdf33333'
+                "af234f",
-//        ], $dto->emails);
+                "asdf33333"
-//        $this->assertInstanceOf(BuyRequest::class, $dto->buy);
+            ],
-//        $this->assertEquals('Buy buy!!!', $dto->buy->phrase);
+            "authors" => [
-//        $this->assertEquals(10, $dto->buy->length);
+                [
-//        $this->assertEquals(true, $dto->buy->isFirst);
+                    "name" => "Tolkien"
-//
+                ],
-//        $this->assertCount(2, $dto->authors);
+                [
-//        $this->assertEquals('Tolkien', $dto->authors[0]->name);
+                    "name" => "Sapkovsky"
-//        $this->assertEquals('Sapkovsky', $dto->authors[1]->name);
+                ]
-//
+            ],
-//        $this->assertInstanceOf(Bar::class, $dto->bar);
+            "authors2" => [
-//        $this->assertIsFloat($dto->bar->barField);
+                [
-//        $this->assertEquals(32.0, $dto->bar->barField);
+                    "name" => "Tolkien"
+                ],
+                [
+                    "name" => "Sapkovsky"
+                ]
+            ],
+            "authors3" => null,
+            "buy" => [
+                "phrase" => "Buy buy!!!",
+                "length" => 10,
+                "isFirst" => true
+            ],
+            "bar" => [
+                "barField" => 32
+            ]
+        ], $dto);
     }
 }

tests/unit/Converter/fixtures/FillTest/HelloRequest.php

@@ -14,6 +14,8 @@ class HelloRequest
     public int $age;
     public array $emails;
     public array $authors;
+    public array $authors2;
+    public array $authors3;
     public BuyRequest $buy;
     public BarInterface $bar;
 }

tests/unit/Converter/fixtures/FillTest/HelloSchema.php

@@ -14,6 +14,10 @@ class HelloSchema extends Schema
         'authors' => [
             'name',
         ],
+        'authors2' => [
+            'name',
+        ],
+        'authors3',
         'buy' => [
             'phrase',
             'length',