diff --git a/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php b/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php
index 785bdfe..7812796 100644
--- a/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php
+++ b/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php
@@ -643,7 +643,12 @@ class InlineParagraphsWidget extends WidgetBase {
         ];
 
         field_group_attach_groups($element['subform'], $context);
-        $element['subform']['#pre_render'][] = 'field_group_form_pre_render';
+        if (function_exists('field_group_form_pre_render')) {
+          $element['subform']['#pre_render'][] = 'field_group_form_pre_render';
+        }
+        if (function_exists('field_group_form_process')) {
+          $element['subform']['#process'][] = 'field_group_form_process';
+        }
       }
 
       if ($item_mode == 'edit') {
diff --git a/src/Plugin/Field/FieldWidget/ParagraphsWidget.php b/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
index c878071..bd22985 100644
--- a/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
+++ b/src/Plugin/Field/FieldWidget/ParagraphsWidget.php
@@ -758,7 +758,12 @@ class ParagraphsWidget extends WidgetBase {
         ];
 
         field_group_attach_groups($element['subform'], $context);
-        $element['subform']['#pre_render'][] = 'field_group_form_pre_render';
+        if (function_exists('field_group_form_pre_render')) {
+          $element['subform']['#pre_render'][] = 'field_group_form_pre_render';
+        }
+        if (function_exists('field_group_form_process')) {
+          $element['subform']['#process'][] = 'field_group_form_process';
+        }
       }
 
       if ($item_mode == 'edit') {