diff --git a/src/Entity/Payment.php b/src/Entity/Payment.php
index d7696c3..53cb25d 100644
--- a/src/Entity/Payment.php
+++ b/src/Entity/Payment.php
@@ -61,11 +61,16 @@ class Payment extends ContentEntityBase implements PaymentInterface {
    * {@inheritdoc}
    */
   public function __construct(array $values, $entity_type, $bundle = FALSE, $translations = array()) {
-    // Unset the values for fields that are stored in the base table. These
-    // values are not needed here, but because the entity storage skips
-    // unserialization, they cause errors.
-    unset($values['payment_method']);
-    unset($values['payment_type']);
+    // Unserialize the values for fields that are stored in the base table,
+    // because the entity storage does not do that.
+    $property_names = ['payment_method', 'payment_type'];
+    foreach ($property_names as $property_name) {
+      if (isset($values[$property_name])) {
+        foreach ($values[$property_name] as &$item_values) {
+          $item_values['plugin_configuration'] = unserialize($item_values['plugin_configuration']);
+        }
+      }
+    }
     parent::__construct($values, $entity_type, $bundle, $translations);
   }
 
diff --git a/src/Plugin/DataType/PluginInstance.php b/src/Plugin/DataType/PluginInstance.php
index 182f3f8..ad48381 100644
--- a/src/Plugin/DataType/PluginInstance.php
+++ b/src/Plugin/DataType/PluginInstance.php
@@ -38,4 +38,13 @@ class PluginInstance extends TypedData {
     parent::setValue($value, $notify);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function __clone() {
+    if ($this->getValue()) {
+      $this->setValue(clone $this->value);
+    }
+  }
+
 }
diff --git a/src/Plugin/Field/FieldType/LineItemItem.php b/src/Plugin/Field/FieldType/LineItemItem.php
index de1643b..585cf90 100644
--- a/src/Plugin/Field/FieldType/LineItemItem.php
+++ b/src/Plugin/Field/FieldType/LineItemItem.php
@@ -14,8 +14,7 @@ use Drupal\payment\Payment;
  *
  * @FieldType(
  *   id = "payment_line_item",
- *   label = @Translation("Payment line item plugins"),
- *   list_class = "\Drupal\payment\Plugin\Field\FieldType\PluginBagItemList"
+ *   label = @Translation("Payment line item plugins")
  * )
  */
 class LineItemItem extends PaymentAwarePluginBagItemBase {
@@ -28,15 +27,4 @@ class LineItemItem extends PaymentAwarePluginBagItemBase {
     return Payment::lineItemManager();
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function onChange($property_name, $notify = TRUE) {
-    if ($this->getParent() instanceof PaymentInterface) {
-      /** @var \Drupal\payment\Plugin\Payment\Method\PaymentMethodInterface $plugin_instance */
-      $plugin_instance = $this->getContainedPluginInstance();
-      $plugin_instance->setPayment($this->getParent());
-    }
-  }
-
 }
diff --git a/src/Plugin/Field/FieldType/PaymentAwarePluginBagItemBase.php b/src/Plugin/Field/FieldType/PaymentAwarePluginBagItemBase.php
index a057b18..abf1019 100644
--- a/src/Plugin/Field/FieldType/PaymentAwarePluginBagItemBase.php
+++ b/src/Plugin/Field/FieldType/PaymentAwarePluginBagItemBase.php
@@ -8,6 +8,7 @@
 namespace Drupal\payment\Plugin\Field\FieldType;
 
 use Drupal\payment\Entity\PaymentInterface;
+use Drupal\payment\PaymentAwareInterface;
 
 /**
  * Provides a plugin bag for payment-aware plugins.
@@ -19,16 +20,18 @@ abstract class PaymentAwarePluginBagItemBase extends PluginBagItemBase {
    */
   public function onChange($property_name, $notify = TRUE) {
     if ($property_name == 'plugin_configuration') {
-      $data = $this;
-      while ($data = $data->getParent()) {
-        if ($data instanceof PaymentInterface) {
-          /** @var \Drupal\payment\PaymentAwareInterface $plugin_instance */
-          $plugin_instance = $this->getContainedPluginInstance();
-          $plugin_instance->setPayment($data);
-          break;
+      $plugin_instance = $this->getContainedPluginInstance();
+      if ($plugin_instance instanceof PaymentAwareInterface) {
+        $data = $this;
+        while ($data = $data->getParent()) {
+          if ($data instanceof PaymentInterface) {
+            $plugin_instance->setPayment($data);
+            break;
+          }
         }
       }
     }
+    parent::onChange($property_name, $notify);
   }
 
 }
diff --git a/src/Plugin/Field/FieldType/PaymentMethodItem.php b/src/Plugin/Field/FieldType/PaymentMethodItem.php
index eeaa0d3..4b0074d 100644
--- a/src/Plugin/Field/FieldType/PaymentMethodItem.php
+++ b/src/Plugin/Field/FieldType/PaymentMethodItem.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\payment\Plugin\Field\FieldType;
 
-use Drupal\payment\Entity\PaymentInterface;
 use Drupal\payment\Payment;
 
 /**
@@ -15,8 +14,7 @@ use Drupal\payment\Payment;
  *
  * @FieldType(
  *   id = "payment_method",
- *   label = @Translation("Payment method plugins"),
- *   list_class = "\Drupal\payment\Plugin\Field\FieldType\PluginBagItemList"
+ *   label = @Translation("Payment method plugins")
  * )
  */
 class PaymentMethodItem extends PaymentAwarePluginBagItemBase {
diff --git a/src/Plugin/Field/FieldType/PaymentStatusItem.php b/src/Plugin/Field/FieldType/PaymentStatusItem.php
index f321c2e..8bde494 100644
--- a/src/Plugin/Field/FieldType/PaymentStatusItem.php
+++ b/src/Plugin/Field/FieldType/PaymentStatusItem.php
@@ -14,8 +14,7 @@ use Drupal\payment\Payment;
  *
  * @FieldType(
  *   id = "payment_status",
- *   label = @Translation("Payment status plugins"),
- *   list_class = "\Drupal\payment\Plugin\Field\FieldType\PluginBagItemList"
+ *   label = @Translation("Payment status plugins")
  * )
  */
 class PaymentStatusItem extends PaymentAwarePluginBagItemBase {
diff --git a/src/Plugin/Field/FieldType/PaymentTypeItem.php b/src/Plugin/Field/FieldType/PaymentTypeItem.php
index 10069ea..bf7e53f 100644
--- a/src/Plugin/Field/FieldType/PaymentTypeItem.php
+++ b/src/Plugin/Field/FieldType/PaymentTypeItem.php
@@ -14,8 +14,7 @@ use Drupal\payment\Payment;
  *
  * @FieldType(
  *   id = "payment_type",
- *   label = @Translation("Payment type plugins"),
- *   list_class = "\Drupal\payment\Plugin\Field\FieldType\PluginBagItemList"
+ *   label = @Translation("Payment type plugins")
  * )
  */
 class PaymentTypeItem extends PaymentAwarePluginBagItemBase {
diff --git a/src/Plugin/Field/FieldType/PluginBagItemBase.php b/src/Plugin/Field/FieldType/PluginBagItemBase.php
index f3435f4..28e140d 100644
--- a/src/Plugin/Field/FieldType/PluginBagItemBase.php
+++ b/src/Plugin/Field/FieldType/PluginBagItemBase.php
@@ -16,7 +16,8 @@ use Drupal\Core\TypedData\MapDataDefinition;
 /**
  * Provides a base for plugin bag field items.
  */
-abstract class PluginBagItemBase extends FieldItemBase implements PluginBagItemInterface {
+abstract class
+PluginBagItemBase extends FieldItemBase implements PluginBagItemInterface {
 
   /**
    * {@inheritdoc}
@@ -180,14 +181,4 @@ abstract class PluginBagItemBase extends FieldItemBase implements PluginBagItemI
     }
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function __clone() {
-    $plugin_instance = $this->get('plugin_instance')->getValue();
-    if (is_object($plugin_instance)) {
-      $this->get('plugin_instance')->setValue(clone $plugin_instance, FALSE);
-    }
-  }
-
 }
diff --git a/src/Plugin/Field/FieldType/PluginBagItemList.php b/src/Plugin/Field/FieldType/PluginBagItemList.php
deleted file mode 100644
index 1b73d7f..0000000
--- a/src/Plugin/Field/FieldType/PluginBagItemList.php
+++ /dev/null
@@ -1,28 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\payment\Plugin\Field\FieldType\PluginBagItemList.
- */
-
-namespace Drupal\payment\Plugin\Field\FieldType;
-
-use Drupal\Core\Field\FieldItemList;
-
-/**
- * Provides a plugin bag field item list.
- */
-class PluginBagItemList extends FieldItemList {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function __clone() {
-    $cloned_items = [];
-    foreach ($this->list as $delta => $item) {
-      $cloned_items[$delta] = clone $item;
-    }
-    $this->list = $cloned_items;
-  }
-
-}