There have been a few cases where the bottom vents on the older kettles have overlapped the leg socket welds or been way off centered with the leg sockets, but I think this is a first for a lid vent that I have seen. It is kind of wild how precise machining has become over the last few decades and how much quality control has improved. It has become especially important as things have become more complex and of course no business likes their customers to go to the internet and highlight their failures.
These days errors occurring so infrequently might actually make something more valuable because they are so rare. Look at coin collecting and error coins as an example.