Pretty much. The Pattern is itself the reason they were Ta'Veren in the first point. To quote Loial, "And sometimes the Wheel bends a life-thread, or several threads, in such a way that all the surrounding threads are forced to swirl around it, and those force other threads, and those still others, and on and on. That first bending to make the Web, that is ta'veren, and there is nothing you can do to change it, not until the Pattern itself changes. The Web - ta'maral'ailen, it's called - can last for weeks, or for years. It can take in a town, or even the whole Pattern. Artur Hawkwing was ta'veren. So was Lews Therin Kinslayer, for that matter, I suppose" (Loial to Rand, The Eye of the World, Chapter 36). [Sourced from library.tarvalon.net]. Robert Jordan also stated that people are not born Ta'Veren [Robert Jordan's Blog, Friday, January 20th, 2006]. So if the Pattern is the force making people Ta'Veren, as a method of 'course correction', then it also makes sense that they would no longer be Ta'Veren when that course is corrected.