Sometimes the date of an edition is not entirely known, OpenLibrary handles this by doing 198x or 18xx, but when hardcover imports dates like these it turns to 0018-01-01

examples:
https://openlibrary.org/books/OL571441M/The_first_part_of_King_Henry_the_Fourth
https://openlibrary.org/books/OL31983242M/Durchs_wilde_Kurdistan