About four years ago, I shot some Kodachrome 25 that expired in 1984 but had been frozen for years before that. It was fine. I also had some frozen Ektachrome 400 and 64 that was left over from a commercial assignment that had expired in 1986 that looked as good as it did when new. For the Ektachrome 400, that meant it still sucked.
I was surprised by the Ektachrome. I had expected some loss of speed or color shift.