diff --git a/CHANGELOG.md b/CHANGELOG.md
index d8beccf0b7a..60ce4948d3b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Release Notes for Craft CMS 4
 
-## Unreleased
+## 4.12.1 - 2024-09-06
 
 - Added `craft\services\Security::isSystemDir()`.
 - Fixed a bug where `craft\helpers\StringHelper::lines()` was returning an array of `Stringy\Stringy` objects, rather than strings.
@@ -8,6 +8,7 @@
 - Fixed a validation error that could occur when saving a relational field, if the “Maintain hierarchy” setting had been enabled but was no longer applicable. ([#15666](https://github.com/craftcms/cms/issues/15666))
 - Fixed a bug where formatted addresses weren’t using the application locale consistently. ([#15668](https://github.com/craftcms/cms/issues/15668))
 - Fixed a bug where Tip and Warning field layout UI elements would display in field layouts even if they had no content. ([#15681](https://github.com/craftcms/cms/issues/15681))
+- Fixed an error that could occur when reverting an element’s content from a revision, if the element had been added to additional sites since the time the revision was created. ([#15679](https://github.com/craftcms/cms/issues/15679))
 - Fixed an information disclosure vulnerability.
 
 ## 4.12.0 - 2024-09-03
diff --git a/src/config/app.php b/src/config/app.php
index 76afb930beb..a0f39ce8c35 100644
--- a/src/config/app.php
+++ b/src/config/app.php
@@ -3,7 +3,7 @@
 return [
     'id' => 'CraftCMS',
     'name' => 'Craft CMS',
-    'version' => '4.12.0',
+    'version' => '4.12.1',
     'schemaVersion' => '4.5.3.0',
     'minVersionRequired' => '3.7.11',
     'basePath' => dirname(__DIR__), // Defines the @app alias
diff --git a/src/services/Elements.php b/src/services/Elements.php
index 0166958ea54..71179d82539 100644
--- a/src/services/Elements.php
+++ b/src/services/Elements.php
@@ -3668,7 +3668,11 @@ private function _propagateElement(
             $siteElement->siteSettingsId = null;
             $siteElement->contentId = null;
             $siteElement->setEnabledForSite($siteInfo['enabledByDefault']);
-            $siteElement->isNewForSite = true;
+            // set isNewForSite to true unless we're reverting content from a revision
+            // in which case, it's possible that the canonical element exists for the site already,
+            // but didn't back when the revision was created.
+            // (see https://github.com/craftcms/cms/issues/15679)
+            $siteElement->isNewForSite = !$siteElement->duplicateOf?->getIsRevision();
 
             // Keep track of this new site ID
             $element->newSiteIds[] = $siteInfo['siteId'];