Fixed issue with mailing group type and multiple.

CHANGELOG.md

 Version 1.14 (under development)
 ============
 
+Version 1.13.2
+============
+
+* Fixed issue with mailing group type and multiple.
+
 Version 1.13.1
 ============
 
-* Fixed issue with mailing group type and multiple,
+* Fixed issue with mailing group type and multiple.
 
 Version 1.13
 ============

Civi/FormProcessor/Type/MailingGroupType.php

@@ -105,7 +105,7 @@ class MailingGroupType extends AbstractType implements OptionListInterface {
    */
   public function denormalizeValue($value) {
     $multiple = $this->configuration->get('multiple') ? TRUE : FALSE;
-    if ($multiple && is_array($value)) {
+    if ($multiple && !is_array($value)) {
       $value = [$value];
     }
     return $value;

info.xml

@@ -16,8 +16,8 @@
     <url desc="Licensing">http://www.gnu.org/licenses/agpl-3.0.html</url>
     <url desc="Action-Provider Extension">https://lab.civicrm.org/extensions/action-provider</url>
   </urls>
-  <releaseDate>2020-09-16</releaseDate>
-  <version>1.14-dev</version>
+  <releaseDate>2020-09-18</releaseDate>
+  <version>1.13.2</version>
   <develStage>stable</develStage>
   <compatibility>
     <ver>4.7</ver>