Notices when subtotals (no aggregation) is enabled

In a view with Group Aggregation selected, when you select the option "no aggregation, results will be shown after each group (like subtotals)" the following notices will pop-up:

Notice: Undefined variable: field_label in Drupal\views_aggregator\Plugin\views\style\Table->setAggregatedGroupValues() (line 1099 of modules\contrib\views_aggregator\src\Plugin\views\style\Table.php).
Notice: Undefined index: in Drupal\views_aggregator\Plugin\views\style\Table->setAggregatedGroupValues() (line 1099 of modules\contrib\views_aggregator\src\Plugin\views\style\Table.php).
Notice: Trying to get property of non-object in Drupal\views_aggregator\Plugin\views\style\Table->getCell() (line 576 of modules\contrib\views_aggregator\src\Plugin\views\style\Table.php).
Notice: Undefined variable: field_label in Drupal\views_aggregator\Plugin\views\style\Table->setAggregatedGroupValues() (line 1100 of modules\contrib\views_aggregator\src\Plugin\views\style\Table.php).