diff --git a/lib/Models/CustomField.php b/lib/Models/CustomField.php
index f8bc223446..63297e33e8 100644
--- a/lib/Models/CustomField.php
+++ b/lib/Models/CustomField.php
@@ -36,7 +36,7 @@ class CustomField extends Model {
     if (isset($model['params'])) {
       $model['params'] = (is_array($this->params))
         ? $this->params
-        : unserialize($this->params);
+        : ($this->params !== null ? unserialize($this->params) : false);
     }
     return $model;
   }
diff --git a/lib/Models/DynamicSegmentFilter.php b/lib/Models/DynamicSegmentFilter.php
index aa7dd66b96..9f14bff94f 100644
--- a/lib/Models/DynamicSegmentFilter.php
+++ b/lib/Models/DynamicSegmentFilter.php
@@ -38,7 +38,7 @@ class DynamicSegmentFilter extends Model {
   public function __get($name) {
     $name = Helpers::camelCaseToUnderscore($name);
     $value = parent::__get($name);
-    if ($name === 'filter_data' && WPFunctions::get()->isSerialized($value)) {
+    if ($name === 'filter_data' && $value !== null && WPFunctions::get()->isSerialized($value)) {
       return unserialize($value);
     }
     return $value;
diff --git a/lib/Models/Form.php b/lib/Models/Form.php
index 2ca3e04500..a99fc590ac 100644
--- a/lib/Models/Form.php
+++ b/lib/Models/Form.php
@@ -16,10 +16,16 @@ class Form extends Model {
   public static $_table = MP_FORMS_TABLE; // phpcs:ignore PSR2.Classes.PropertyDeclaration
 
   public function getSettings() {
+    if (is_array($this->settings) || $this->settings === null) {
+      return $this->settings;
+    }
     return WPFunctions::get()->isSerialized($this->settings) ? unserialize($this->settings) : $this->settings;
   }
 
   public function getBody() {
+    if (is_array($this->body) || $this->body === null) {
+      return $this->body;
+    }
     return WPFunctions::get()->isSerialized($this->body) ? unserialize($this->body) : $this->body;
   }
 
diff --git a/lib/Models/SendingQueue.php b/lib/Models/SendingQueue.php
index 1edcdfa4e1..d544706bc2 100644
--- a/lib/Models/SendingQueue.php
+++ b/lib/Models/SendingQueue.php
@@ -91,7 +91,7 @@ class SendingQueue extends Model {
    * Used only for checking processed subscribers in old queues
    */
   private function getSubscribers() {
-    if (!is_serialized($this->subscribers)) {
+    if (is_array($this->subscribers) || $this->subscribers === null || !is_serialized($this->subscribers)) {
       return $this->subscribers;
     }
     $subscribers = unserialize($this->subscribers);