One of the very first signs of doubt was from a convention signed that referenced the 1975 prediction. They cited a 1968 watchtower article. The generation change was earth shattering to me. It seemed like no one else was bothered by this major doctrinal shift.
Recently, through YouTube testimonies, I have noticed, that many were affected by this change.
Whatever is causing people to leave the organization TODAY, may not be realized for decades.