diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/DocblockReturnArrayFromDirectArrayInstanceRector/Fixture/repeated_item_type.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/DocblockReturnArrayFromDirectArrayInstanceRector/Fixture/repeated_item_type.php.inc
new file mode 100644
index 00000000000..9bc257ac9f9
--- /dev/null
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/DocblockReturnArrayFromDirectArrayInstanceRector/Fixture/repeated_item_type.php.inc
@@ -0,0 +1,66 @@
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\ClassMethod\DocblockReturnArrayFromDirectArrayInstanceRector\Fixture;
+
+final class RepeatedItemType
+{
+    public function __construct(
+        public readonly string $collectionName,
+        public readonly ?string $partitionName = null,
+        public readonly ?int $replicaNumber = null,
+        public readonly ?int $timeout = null,
+    ) {}
+
+    public function toRequestPayload(): array
+    {
+        $params = [
+            'partition_name' => $this->partitionName,
+            'replica_number' => $this->replicaNumber,
+            'timeout' => $this->timeout,
+        ];
+
+        $params = array_filter($params);
+
+        return [
+            'collection_name' => $this->collectionName,
+            'params' => $params,
+        ];
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\ClassMethod\DocblockReturnArrayFromDirectArrayInstanceRector\Fixture;
+
+final class RepeatedItemType
+{
+    public function __construct(
+        public readonly string $collectionName,
+        public readonly ?string $partitionName = null,
+        public readonly ?int $replicaNumber = null,
+        public readonly ?int $timeout = null,
+    ) {}
+
+    /**
+     * @return array<string, string|array<string, int|string>>
+     */
+    public function toRequestPayload(): array
+    {
+        $params = [
+            'partition_name' => $this->partitionName,
+            'replica_number' => $this->replicaNumber,
+            'timeout' => $this->timeout,
+        ];
+
+        $params = array_filter($params);
+
+        return [
+            'collection_name' => $this->collectionName,
+            'params' => $params,
+        ];
+    }
+}
+
+?>
diff --git a/src/BetterPhpDocParser/ValueObject/Type/BracketsAwareUnionTypeNode.php b/src/BetterPhpDocParser/ValueObject/Type/BracketsAwareUnionTypeNode.php
index 3325bf3ba07..15cdcc4252a 100644
--- a/src/BetterPhpDocParser/ValueObject/Type/BracketsAwareUnionTypeNode.php
+++ b/src/BetterPhpDocParser/ValueObject/Type/BracketsAwareUnionTypeNode.php
@@ -25,6 +25,7 @@ public function __construct(
      */
     public function __toString(): string
     {
+        $this->types = array_unique($this->types, SORT_REGULAR);
         if (! $this->isWrappedInBrackets) {
             return implode('|', $this->types);
         }