I am a bit perplexed by this and would like clarification by any Jehovah's Witness who might be reading this:
December 1, 1984 Watchtower:
"....Have apostates who claim that "the last days" began at Pentecost and cover the entire Christian Era promoted Christian alertness? Have they not, rather, induced spiritual sleepiness?...."
February 15, 2008 Watchtower:
".....Since Jesus did not use negative qualifiers when speaking to them about "this generation," the apostles would no doubt have understood that they and their fellow disciples were to be part of the "generation" that would not pass away "until all these things [would] occur....."
I don't have the full articles, which might make more sense given the fuller context. But what i'm seeing here seems to be saying that those who claimed that the last days began at pentecost are "apostates." This was said in 1984. But then in 2008 it was said that the apostles understood the last days as happening in their lifetime. Unless i'm mistaken, this seems to be an instance of careless stone-throwing by the Watchtower.