Without a shadow of doubt, there have been many untruths told to JWs over the last 130 years that were changed, yet without the leaders admitting that they had made errors initially, as they try to pretend they now have 'brighter light' on the teaching.
Take, for instance, the lie about the 144,000 number being literal. That doctrine was only brought in around 1935 when leaders claimed God had revealed to them that only 144,000 humans (from the time of Christ till Armageddon) would ever get to Heaven; all new converts to the JWs would be in an earthly class. They also said the heavenly calling was just about wrapped up back then, with only a tiny few 'replacements' needed when some of the anointed lost their heavenly calling. Well, 80+ years later, that doctrine has been blown out of the water with big increases year on year with JWs claiming to now have the heavenly calling. Necessity is forcing the leaders to prepare the ground to change the doctrine, to say the number must be symbolic, because the figures just don't stack up any longer.
Now, to avoid the charge of lying to JWs, the leaders need to just openly admit that the 1935 idea was a wrong idea and that they are going back to the view the first president had, in the late 1800s, that there would be two groups in Heaven, not just one tiny group of 144,000 people. Today's leaders just will not do that as that would prove they do not have the Holy Spirit's anointing. So, in order to keep all their followers unquestioningly accepting all changes in doctrine, they claim God is making the light brighter. That is a lie. The 'light' switch is being switched on and off.
It's one thing to make an honest mistake then to later admit it, but to claim the original idea was changed because God told the leaders a unique doctrine, then 80+ years later to 'adjust' the doctrine because God has given them 'increased light' on the subject, is a simple lie. Any Bible student who believes Jude verse 3 should know that. Had a literal numeric limit for getting into Heaven been God's truth, the apostles back then would have known it and taught it. They did not. The literal number idea of the 1930s is untrue and is now being exposed as a JW lie that is deceived millions, actively helping to keep them out of the Kingdom of Heaven.