diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/DocblockReturnArrayFromDirectArrayInstanceRector/Fixture/Nesting/not_too_complex.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/DocblockReturnArrayFromDirectArrayInstanceRector/Fixture/Nesting/not_too_complex.php.inc
new file mode 100644
index 00000000000..20f86cb5131
--- /dev/null
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/DocblockReturnArrayFromDirectArrayInstanceRector/Fixture/Nesting/not_too_complex.php.inc
@@ -0,0 +1,44 @@
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\ClassMethod\DocblockReturnArrayFromDirectArrayInstanceRector\Fixture\Nesting;
+
+final class AvoidExtremeNesting
+{
+   public function run(): array
+    {
+        return [
+            'key1' => 123,
+            'key2' => '456.7',
+            'key3' => 89.0,
+            'key4' => -42,
+            'key5' => '12%',
+            'key6' => -9999,
+        ];
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\ClassMethod\DocblockReturnArrayFromDirectArrayInstanceRector\Fixture\Nesting;
+
+final class AvoidExtremeNesting
+{
+   /**
+    * @return array<string, int|string|float>
+    */
+   public function run(): array
+    {
+        return [
+            'key1' => 123,
+            'key2' => '456.7',
+            'key3' => 89.0,
+            'key4' => -42,
+            'key5' => '12%',
+            'key6' => -9999,
+        ];
+    }
+}
+
+?>
diff --git a/rules/Privatization/TypeManipulator/TypeNormalizer.php b/rules/Privatization/TypeManipulator/TypeNormalizer.php
index cf395806d90..90664309bdd 100644
--- a/rules/Privatization/TypeManipulator/TypeNormalizer.php
+++ b/rules/Privatization/TypeManipulator/TypeNormalizer.php
@@ -98,7 +98,7 @@ public function generalizeConstantTypes(Type $type): Type
                 $uniqueGeneralizedUnionTypes = $this->typeFactory->uniquateTypes($generalizedUnionedTypes);
 
                 if (count($uniqueGeneralizedUnionTypes) > 1) {
-                    $generalizedUnionType = new UnionType($generalizedUnionedTypes);
+                    $generalizedUnionType = new UnionType($uniqueGeneralizedUnionTypes);
                     // avoid too huge print in docblock
                     $unionedDocType = $this->staticTypeMapper->mapPHPStanTypeToPHPStanPhpDocTypeNode(
                         $generalizedUnionType