PHP Fatal error: Declaration of Drupal\panels\Form\PanelsAddBlockForm::buildForm

PHP Fatal error:  Declaration of Drupal\panels\Form\PanelsAddBlockForm::buildForm(array $form, Drupal\Core\Form\FormStateInterface $form_state, ?Symfony\Component\HttpFoundation\Request $request = NULL, $tempstore_id = NULL, $machine_name = NULL, $block_id = NULL) must be compatible with Drupal\panels\Form\PanelsBlockConfigureFormBase::buildForm(array $form, Drupal\Core\Form\FormStateInterface $form_state, $tempstore_id = NULL, $machine_name = NULL, $block_id = NULL) in docroot/modules/contrib/panels/src/Form/PanelsAddBlockForm.php on line 14

Using PHP 7.2 & Drupal core 8.5.0.