I guess I'll quote myself from upthread: the last time that two less-than-nine inning no-hitters have happened in the same season was....1990, when Melido Perez threw a six-inning rain-shortened no-hitter and Andy Hawkins threw an eight-inning complete game no-hitter. Somehow, both games involved the White Sox winning and the Yankees losing, and somehow both games had Andy Hawkins as the losing pitcher.
The other post-deadball year with two shortened no-nos was 1959; that year, both no-no's were thrown (and won) by Giants' pitchers.
The all-time record for shortened no-nos in a season is four, which happened in 1907.