Merge branch '4.x' of https://github.com/craftcms/cms into 5.x

# Conflicts:
#	CHANGELOG.md

CHANGELOG.md

@@ -9,6 +9,7 @@
 - Fixed errors that could occur if a custom source or field condition referenced a custom field whose type had changed. ([#15850](https://github.com/craftcms/cms/issues/15850))
 - Fixed a bug where disclosure menus weren’t sticking to their trigger element as it was scrolled, if it was within a slideout or other inline-scrollable container. ([#15852](https://github.com/craftcms/cms/issues/15852))
 - Fixed a bug where the default backup command for MySQL was exporting triggers twice. ([#15854](https://github.com/craftcms/cms/pull/15854))
+- Fixed a bug where Multi-select fields were saving the selected options in the user-selected order rather than the field-defined order. ([#15857](https://github.com/craftcms/cms/issues/15857))
 - Fixed a bug where field toggling wasn’t working properly for boolean menus and radio groups.
 - Fixed a bug where eager-loading wasn’t working properly when multiple fields had the same handle. ([#15796](https://github.com/craftcms/cms/issues/15796))
 - Fixed a bug where where required Full Name fields weren’t getting enforced for users. ([#15808](https://github.com/craftcms/cms/issues/15808))

src/fields/BaseOptionsField.php

@@ -360,9 +360,11 @@ public function serializeValue(mixed $value, ?ElementInterface $element): mixed
     {
         if ($value instanceof MultiOptionsFieldData) {
             $serialized = [];
-            foreach ($value as $selectedValue) {
-                /** @var OptionData $selectedValue */
-                $serialized[] = $selectedValue->value;
+            // Build the list out in the original option order
+            foreach ($value->getOptions() as $option) {
+                if ($option->selected) {
+                    $serialized[] = $option->value;
+                }
             }
             return $serialized;
         }