Have ti turn on Write for Read to Work?

 In some (but not all projects), the fader automation does not work unless I have WRITE turned enabled on the track, even though READ is on. Is there some strange function I am not aware of that would cause this behavior? To explain further: Project 1: turn on WRTIE to set faders. Once done, I turn WRITE off but leave READ on. Faders moves as they should, Project 2: turn on WRITE to set faders. Once done, I turn WRITE off but leave READ on. Faders do nothing even though I see in the track that my automation was recorded. I have to turn WRTIE on to get the faders to move. WTH?