The 5/17/2018 episode aired out west, although the second Showcase Showdown and most of the first Showcase were pre-empted by coverage of the Bush casket being put aboard the train.
As for when the new episodes will air, I assume that as soon as CBS decides, the airdate list will be updated. The only remaining days before the end of June that I can think of when they have repeats scheduled but could air new episodes are March 19 and 20.