5.x: undefined index notices about bootstrap-ui HOT 4 CLOSED

$options = $this->_spacingOptions($fieldName, $options);
// NOW it gets nuked:
$options = $this->_containerOptions($fieldName, $options);
$options = $this->_feedbackStyleOptions($fieldName, $options);

        if (
            $this->_align !== static::ALIGN_INLINE &&
            isset($options['type']) &&
            $options['spacing'] !== false
        ) {
            $classes = $options['spacing'] ?? [];
            $options = (array)($options['container'] ?? []);
            $options['container'] = $this->injectClasses($classes, $options);
        }