"Jehovah's Witnesses have had wrong expectations about when the end would come."
Not a huge point, but notice they don't say the Faithful & Discreet Slave or the Governing Body got it wrong. Jehovah's Witnesses got it wrong. That could include individual JWs with their own unofficial timetables.
Again, not a huge point, but it does have a subtle effect on the meaning of the sentence.
om