diff --git a/CHANGELOG.md b/CHANGELOG.md
index 21e7c8f5b1..ea467fbb79 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 - Added the `commerce/gateways/webhook-url` command.
 - Fixed a bug where the delete button would be shown for users that do not have permission to delete on the Product edit page. ([#3285](https://github.com/craftcms/commerce/issues/3285))
 - Fixed a bug where deleted shipping categories were still available for selection. ([#3272](https://github.com/craftcms/commerce/issues/3272))
+- Fixed a bug where the customer condition rule wasn’t loading correctly. ([#3291](https://github.com/craftcms/commerce/issues/3291))
 - Fixed an error that could occur when rendering a PDF. ([#2633](https://github.com/craftcms/commerce/issues/2633))
 - Fixed a bug where duplicate inactive users could be created when using the `commerce/upgrade` command. ([#3286](https://github.com/craftcms/commerce/issues/3286))
 
diff --git a/src/elements/conditions/orders/CustomerConditionRule.php b/src/elements/conditions/orders/CustomerConditionRule.php
index 02aa7d9ac4..00248bfc69 100644
--- a/src/elements/conditions/orders/CustomerConditionRule.php
+++ b/src/elements/conditions/orders/CustomerConditionRule.php
@@ -15,13 +15,17 @@
 use craft\elements\conditions\ElementConditionRuleInterface;
 use craft\elements\db\ElementQueryInterface;
 use craft\elements\User;
+use craft\helpers\Cp;
+use craft\helpers\Db;
 use yii\base\InvalidConfigException;
+use yii\db\Expression;
 
 /**
  * Customer Condition Rule
  *
  * @author Pixel & Tonic, Inc. <support@pixelandtonic.com>
  * @since 4.2.0
+ * @TODO change the class that the `CustomerConditionRule` extends
  */
 class CustomerConditionRule extends BaseMultiSelectConditionRule implements ElementConditionRuleInterface
 {
@@ -35,6 +39,7 @@ public function getLabel(): string
 
     /**
      * @return array
+     * @deprecated in 4.3.1.
      */
     protected function options(): array
     {
@@ -47,6 +52,24 @@ protected function options(): array
             ->all();
     }
 
+    /**
+     * @inheritDoc
+     */
+    protected function inputHtml(): string
+    {
+        $users = User::find()->status(null)->limit(null)->id($this->values)->all();
+
+        return Cp::elementSelectHtml([
+            'name' => 'values',
+            'elements' => $users,
+            'elementType' => User::class,
+            'sources' => null,
+            'criteria' => null,
+            'condition' => null,
+            'single' => false,
+        ]);
+    }
+
     /**
      * @inheritdoc
      */
@@ -63,10 +86,11 @@ public function modifyQuery(ElementQueryInterface $query): void
         /** @var OrderQuery $query */
         $paramValue = $this->paramValue();
         if ($this->operator === self::OPERATOR_NOT_IN) {
-            $paramValue = ['or', $paramValue, null];
+            // Account for the fact the querying using a combination of `not` and `in` doesn't match `null` in the column
+            $query->andWhere(Db::parseParam(new Expression('coalesce([[commerce_orders.customerId]], -1)'), $paramValue));
+        } else {
+            $query->customerId($paramValue);
         }
-
-        $query->customerId($paramValue);
     }
 
     /**