Ballot Access News has just learned that in 2018, the Kentucky deadline for non-presidential independent candidate deadlines was moved from August to early June. However, no change was made to the petition deadline for presidential candidates, which is still in September. Thanks to Ken Moellman for this news.
It is not likely that the June deadline for office other than president is unconstitutional, because the Kentucky primary is in May. Generally, for office other than president, courts allow the petition deadlines to be somewhat early in the year, as long as that petition deadline is later than the primary.