diff --git a/classes/issue/DAO.php b/classes/issue/DAO.php
index c76f9e2b479..a981d79a2c8 100644
--- a/classes/issue/DAO.php
+++ b/classes/issue/DAO.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file classes/issue/DAO.php
  *
@@ -308,7 +309,7 @@ public function pubIdExists(string $pubIdType, string $pubId, int $excludePubObj
         return DB::table('issue_settings AS ist')
             ->join('issues AS i', 'ist.issue_id', '=', 'i.issue_id')
             ->where('ist.setting_name', '=', "pub-id::{$pubIdType}")
-            ->where('ist.setting_value', '<>', $pubId)
+            ->where('ist.setting_value', '=', $pubId)
             ->where('i.issue_id', '<>', $excludePubObjectId)
             ->where('i.journal_id', '=', $contextId)
             ->count() > 0;
diff --git a/classes/journal/JournalDAO.php b/classes/journal/JournalDAO.php
index 68c2c778261..5b1b716e38b 100644
--- a/classes/journal/JournalDAO.php
+++ b/classes/journal/JournalDAO.php
@@ -118,7 +118,7 @@ public function anyPubIdExists(
         $pubObjectDaos = [
             Application::ASSOC_TYPE_ISSUE => Repo::issue()->dao,
             Application::ASSOC_TYPE_PUBLICATION => Repo::publication()->dao,
-            Application::ASSOC_TYPE_GALLEY => Application::getRepresentationDAO(),
+            Application::ASSOC_TYPE_REPRESENTATION => Application::getRepresentationDAO(),
             Application::ASSOC_TYPE_ISSUE_GALLEY => DAORegistry::getDAO('IssueGalleyDAO'),
             Application::ASSOC_TYPE_SUBMISSION_FILE => Repo::submissionFile()->dao,
         ];
diff --git a/classes/plugins/PubIdPlugin.php b/classes/plugins/PubIdPlugin.php
index e0102724d21..37e743402fc 100644
--- a/classes/plugins/PubIdPlugin.php
+++ b/classes/plugins/PubIdPlugin.php
@@ -140,18 +140,16 @@ public function getPubObjectTypes()
     /**
      * @copydoc PKPPubIdPlugin::checkDuplicate()
      */
-    public function checkDuplicate($pubId, $pubObjectType, $excludeId, $contextId)
+    public function checkDuplicate($pubId, $pubObject, $contextId)
     {
-        foreach ($this->getPubObjectTypes() as $type => $fqcn) {
-            if ($type === 'Issue') {
-                $excludeTypeId = $type === $pubObjectType ? $excludeId : null;
-                if (Repo::issue()->dao->pubIdExists($this->getPubIdType(), $pubId, $excludeTypeId, $contextId)) {
-                    return false;
-                }
+        $allowedPubObjectTypes = $this->getPubObjectTypes();
+        if ($pubObject instanceof $allowedPubObjectTypes['Issue']) {
+            if (Repo::issue()->dao->pubIdExists($this->getPubIdType(), $pubId, $pubObject->getId(), $contextId)) {
+                return false;
             }
+            return true;
         }
-
-        return parent::checkDuplicate($pubId, $pubObjectType, $excludeId, $contextId);
+        return parent::checkDuplicate($pubId, $pubObject, $contextId);
     }
 
     /**
diff --git a/plugins/pubIds/urn/URNPubIdPlugin.php b/plugins/pubIds/urn/URNPubIdPlugin.php
index 3080fef68b1..a12acdcba35 100755
--- a/plugins/pubIds/urn/URNPubIdPlugin.php
+++ b/plugins/pubIds/urn/URNPubIdPlugin.php
@@ -21,6 +21,7 @@
 use APP\plugins\PubIdPlugin;
 use APP\plugins\pubIds\urn\classes\form\FieldPubIdUrn;
 use APP\plugins\pubIds\urn\classes\form\FieldTextUrn;
+use APP\plugins\pubIds\urn\classes\form\URNSettingsForm;
 use APP\template\TemplateManager;
 use PKP\components\forms\FormComponent;
 use PKP\components\forms\publication\PKPPublicationIdentifiersForm;
@@ -157,7 +158,7 @@ public function getPubIdAssignFile()
      */
     public function instantiateSettingsForm($contextId)
     {
-        return new classes\form\URNSettingsForm($this, $contextId);
+        return new URNSettingsForm($this, $contextId);
     }
 
     /**
@@ -312,7 +313,7 @@ public function validatePublicationUrn(string $hookName, array $args): void
         if (strpos($props['pub-id::other::urn'], $urnPrefix) !== 0) {
             $urnErrors[] = __('plugins.pubIds.urn.editor.missingPrefix', ['urnPrefix' => $urnPrefix]);
         }
-        if (!$this->checkDuplicate($props['pub-id::other::urn'], 'Publication', $submission->getId(), $contextId)) {
+        if (!$this->checkDuplicate($props['pub-id::other::urn'], $publication, $contextId)) {
             $urnErrors[] = $this->getNotUniqueErrorMsg();
         }
         if (!empty($urnErrors)) {