Other Bookable Calendar date token not working in User Email Notification

That's a new token that got added and seems like the method it calls didn't make its way into the commit. That is now in latest dev.

I just tried the latest dev build and when including the date token I now get this error:

Drupal\Core\Entity\EntityStorageException: The timestamp must be numeric. in Drupal\Core\Entity\Sql\SqlContentEntityStorage->save() (line 815 of /home/mysite/public_html/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php).

Alright have another fix, and I tested this one and it should actually fix the issue.