Force view to be built before trying to render it.

modules/ui_patterns_views/src/Plugin/UiPatterns/Source/ViewFieldSource.php

@@ -40,6 +40,7 @@ class ViewFieldSource extends ViewsSourceBase {
       return ['#markup' => ''];
     }
     // Get the output of the field.
+    $view->build();
     $field_output = $view->style_plugin->getField($row_index, $field_name);
     // Remove field if need it.
     if ($this->isViewFieldHidden($field_name, $field_output, $view)) {