WSOD for OfficeHoursExceptionsSlot since update to 8.x-1.8+dev

This comes from #3359690-7: Error when date field is left blank → , but I do not understand why.
The system should fetch the OfficeHoursListSlot automatically.

Please run /update.php to clear all caches.
If that does not work, add the line as shown below in the code.
Please report back.

namespace Drupal\office_hours\Element;

use Drupal\Core\Form\FormStateInterface;
use Drupal\office_hours\Element\OfficeHoursListSlot;  // <-- ADD THIS LINE

/**
 * Provides a one-line text field form element for Exception days.
 *
 * @FormElement("office_hours_exceptions_slot")
 */
class OfficeHoursExceptionsSlot extends OfficeHoursListSlot {
  //...
}

Please try newest dev version. A fix is committed in #3359690-13: Error when date field is left blank →
Apparently, my system is case insensitive, yours is not.

The version solves the problem :-)

nice.

Automatically closed - issue fixed for 2 weeks with no activity.