app-functions-fn.common.php.diff

diff --git a/app/functions/fn.common.php b/app/functions/fn.common.php
index 4bf36ce..7ccd1fb 100644
--- a/app/functions/fn.common.php
+++ b/app/functions/fn.common.php
@@ -5877,7 +5877,7 @@ function fn_live_editor_prepare_callback_args($schema, $vars)
  * @param $operator
  * @param $right_operand
  *
- * @return bool Comparison result
+ * @return bool|null Boolean comparison result or null if unknown operator given
  */
 function fn_compare_values_by_operator($left_operand, $operator, $right_operand)
 {
@@ -5943,9 +5943,9 @@ function fn_compare_values_by_operator($left_operand, $operator, $right_operand)
         } else {
             return !in_array($left_operand, $right_operand);
         }
-    } else {
-        throw new InvalidArgumentException('Unknown operator given');
     }
+
+    return null;
 }
 
 /**

app-functions-fn.promotions.php.diff

diff --git a/app/functions/fn.promotions.php b/app/functions/fn.promotions.php
index a67a7ea..a934b0c 100644
--- a/app/functions/fn.promotions.php
+++ b/app/functions/fn.promotions.php
@@ -933,6 +933,11 @@ function fn_promotion_validate_attribute($value, $condition, $op)
 
     fn_set_hook('pre_validate_promotion_attribute', $value, $condition, $op, $result);
 
+    // Modified at hook handler
+    if ($result) {
+        return true;
+    }
+
     $val = !is_array($value) ? array($value) : $value;
 
     if ($op == 'neq') {