BUG: Index.is_monotonic... incorrectly caching Index.is_unique when first value is NaT#55755

mroeschke merged 2 commits intopandas-dev:mainpandas-dev/pandas:mainfrom

lukemanley:datelike-is-unique-with-natlukemanley/pandas:datelike-is-unique-with-natCopy head branch name to clipboard