I remember reading about that, maybe in Crisis of Conscience. I think 1925 had a huge effect on any future predictions. Because they rely on out-of-time urgency, they never stopped predicting the end of the world. But they tried to use language that wasn't as clear and definite as Rutherford had repeatedly used regarding 1925.
Of course, they still slipped up from time-to-time. Most of the times they hinted at a date, they would occasionally use language that was all too clear. Unless they think that "the next few years" refers to more than 80 years.