diff --git a/src/Psalm/Internal/Type/TemplateInferredTypeReplacer.php b/src/Psalm/Internal/Type/TemplateInferredTypeReplacer.php
index 2922f3b8d32..46d028351f4 100644
--- a/src/Psalm/Internal/Type/TemplateInferredTypeReplacer.php
+++ b/src/Psalm/Internal/Type/TemplateInferredTypeReplacer.php
@@ -117,7 +117,7 @@ public static function replace(
                             $is_mixed = true;
                         }
 
-                        $new_types[$template_type_part->getKey()] = $template_type_part;
+                        $new_types[] = $template_type_part;
                     }
                 }
             } elseif ($atomic_type instanceof Atomic\TTemplateParamClass) {
@@ -153,7 +153,7 @@ public static function replace(
 
                 if ($class_template_type) {
                     $keys_to_unset[] = $key;
-                    $new_types[$class_template_type->getKey()] = $class_template_type;
+                    $new_types[] = $class_template_type;
                 }
             } elseif ($atomic_type instanceof Atomic\TTemplateIndexedAccess) {
                 $keys_to_unset[] = $key;
@@ -194,10 +194,10 @@ public static function replace(
                             $is_mixed = true;
                         }
 
-                        $new_types[$template_type_part->getKey()] = $template_type_part;
+                        $new_types[] = $template_type_part;
                     }
                 } else {
-                    $new_types[$key] = new Atomic\TMixed();
+                    $new_types[] = new Atomic\TMixed();
                 }
             } elseif ($atomic_type instanceof Atomic\TConditional
                 && $codebase
@@ -347,7 +347,7 @@ public static function replace(
                 $keys_to_unset[] = $key;
 
                 foreach ($class_template_type->getAtomicTypes() as $class_template_atomic_type) {
-                    $new_types[$class_template_atomic_type->getKey()] = $class_template_atomic_type;
+                    $new_types[] = $class_template_atomic_type;
                 }
             }
         }
@@ -359,7 +359,12 @@ public static function replace(
                 throw new \UnexpectedValueException('This array should be full');
             }
 
-            $union->replaceTypes($new_types);
+            $union->replaceTypes(
+                TypeCombiner::combine(
+                    $new_types,
+                    $codebase
+                )->getAtomicTypes()
+            );
 
             return;
         }
diff --git a/tests/Template/ClassTemplateTest.php b/tests/Template/ClassTemplateTest.php
index 90398a89b63..5b8824612bc 100644
--- a/tests/Template/ClassTemplateTest.php
+++ b/tests/Template/ClassTemplateTest.php
@@ -3371,6 +3371,32 @@ function writesLikeAnArray(WeakMap $wm): void {
                     }
                 ',
             ],
+            'combineTwoTemplatedArrays' => [
+                '<?php
+                    /** @template T */
+                    class Option
+                    {
+                        /** @param T $v */
+                        public function __construct(private $v) {}
+
+                        /**
+                         * @template E
+                         * @param E $else
+                         * @return T|E
+                         */
+                        public function getOrElse($else)
+                        {
+                           return rand(0, 1) === 1 ? $this->v : $else;
+                        }
+                    }
+
+                    $opt = new Option([1, 3]);
+
+                    $b = $opt->getOrElse([2, 4])[0];',
+                [
+                    '$b===' => '1|2'
+                ]
+            ],
         ];
     }