I have the issue with the 'Talkback is activated' notification that will not go away.
I do have low vision, so I had set up my phone so that when I tripple clicked the home button, it would enable talkback. I then discovered that the talkback is terrible, and no longer wanted to use it. So I changed my settings to remove the tipple-click home button feature. Now, I have the 'talkback is activated' notification that will not go away. To get rid of it, I did a factory reset of my phone, which was a pain to have to set up all my e mail accounts and settings, but the notification was finally gone. But, the other day, the notification appeared again, and will not go away. This time, it just started appearing after I tried to use the microphone button on the keyboard to speak some text into my phone.
Anyhow, I go into the Accessibility > Vision section of my settings, and it shows talkback is Off. And even if I turn it on, and then turn it back off again, the notification stays. I have gone into Settings > Applications and tried to disable Galaxy Talkback, but it does not allow me to. The 'Disable' button is grayed-out.
It is not a huge deal that the notification is there, I can still use my phone fine, but it is very annoying. I just got the phone, and I don't want to have to deal with that notification on my screen every time I turn my phone on for the rest of the time I own it.
Ps. I've had several other bugs happening with this phone. not impressed. This is my first Android phone, coming from Apple, so i am not sure if these little bugs are typical, or if the galaxy S6 just needs some work.