diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d91eca8..f59a4807 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ## 2.6.1 under development
 
-- no changes in this release.
+- Bug #817: Fix `UniqueIterable` comparing the whole iterable instead of its items (@CorvusSharp)
 
 ## 2.6.0 June 02, 2026
 
diff --git a/src/Rule/UniqueIterableHandler.php b/src/Rule/UniqueIterableHandler.php
index a06cb7a3..7f20739c 100644
--- a/src/Rule/UniqueIterableHandler.php
+++ b/src/Rule/UniqueIterableHandler.php
@@ -57,22 +57,22 @@ public function validate(mixed $value, RuleInterface $rule, ValidationContext $c
 
             $previousItem = $item;
 
-            if (!empty($stack) && count($stack) !== count(array_unique($stack, flags: SORT_REGULAR))) {
-                return (new Result())->addError($rule->getMessage(), [
-                    'property' => $context->getTranslatedProperty(),
-                    'Property' => $context->getCapitalizedTranslatedProperty(),
-                ]);
-            }
-
-            if ($value instanceof Stringable) {
-                $stack[] = (string) $value;
-            } elseif ($value instanceof DateTimeInterface) {
-                $stack[] = $value->getTimestamp();
+            if ($item instanceof Stringable) {
+                $stack[] = (string) $item;
+            } elseif ($item instanceof DateTimeInterface) {
+                $stack[] = $item->getTimestamp();
             } else {
-                $stack[] = $value;
+                $stack[] = $item;
             }
         }
 
+        if (count($stack) !== count(array_unique($stack, flags: SORT_REGULAR))) {
+            return (new Result())->addError($rule->getMessage(), [
+                'property' => $context->getTranslatedProperty(),
+                'Property' => $context->getCapitalizedTranslatedProperty(),
+            ]);
+        }
+
         return new Result();
     }
 
diff --git a/tests/Rule/UniqueIterableTest.php b/tests/Rule/UniqueIterableTest.php
index d2f835c0..ac6031d7 100644
--- a/tests/Rule/UniqueIterableTest.php
+++ b/tests/Rule/UniqueIterableTest.php
@@ -120,6 +120,40 @@ public function __toString()
                 [new DateTime('2024-04-10 14:05:01'), new DateTime('2024-04-10 14:05:02')],
                 new UniqueIterable(),
             ],
+            'more than two unique strings' => [['a', 'b', 'c'], new UniqueIterable()],
+            'more than two unique integers' => [[1, 2, 3, 4], new UniqueIterable()],
+            'more than two unique floats' => [[1.5, 2.5, 3.5], new UniqueIterable()],
+            'more than two unique stringable values' => [
+                [
+                    new class implements Stringable {
+                        public function __toString()
+                        {
+                            return 'a';
+                        }
+                    },
+                    new class implements Stringable {
+                        public function __toString()
+                        {
+                            return 'b';
+                        }
+                    },
+                    new class implements Stringable {
+                        public function __toString()
+                        {
+                            return 'c';
+                        }
+                    },
+                ],
+                new UniqueIterable(),
+            ],
+            'more than two unique datetime values' => [
+                [
+                    new DateTime('2024-04-10 14:05:01'),
+                    new DateTime('2024-04-10 14:05:02'),
+                    new DateTime('2024-04-10 14:05:03'),
+                ],
+                new UniqueIterable(),
+            ],
             'using as attribute' => [
                 new class {
                     #[UniqueIterable]
@@ -213,6 +247,43 @@ public function getRules(): array
                 null,
                 ['data' => ['"Данные" - в списке есть недопустимое значение.']],
             ],
+            'two equal strings' => [['a', 'a'], new UniqueIterable(), ['' => [$message]]],
+            'duplicate loses to a later disallowed item' => [
+                [1, 1, []],
+                new UniqueIterable(),
+                ['' => [$incorrectItemValueMessage]],
+            ],
+            'duplicate loses to a later type mismatch' => [
+                ['data' => [1, 1, 'a']],
+                ['data' => new UniqueIterable()],
+                ['data' => ['All iterable items of data must have the same type.']],
+            ],
+            'two equal integers' => [[1, 1], new UniqueIterable(), ['' => [$message]]],
+            'two equal floats' => [[1.5, 1.5], new UniqueIterable(), ['' => [$message]]],
+            'two equal boolean values' => [[true, true], new UniqueIterable(), ['' => [$message]]],
+            'two equal stringable values' => [
+                [
+                    new class implements Stringable {
+                        public function __toString()
+                        {
+                            return 'a';
+                        }
+                    },
+                    new class implements Stringable {
+                        public function __toString()
+                        {
+                            return 'a';
+                        }
+                    },
+                ],
+                new UniqueIterable(),
+                ['' => [$message]],
+            ],
+            'two equal datetime values' => [
+                [new DateTime('2024-04-10 14:05:01'), new DateTime('2024-04-10 14:05:01')],
+                new UniqueIterable(),
+                ['' => [$message]],
+            ],
             'strings' => [['a', 'b', 'a', 'c'], new UniqueIterable(), ['' => [$message]]],
             'integers' => [[1, 2, 1, 3], new UniqueIterable(), ['' => [$message]]],
             'floats' => [[1.5, 2.5, 1.5, 3.5], new UniqueIterable(), ['' => [$message]]],