Reply to Noob question about the mixer

I've just noticed this issue in the past day and a half, and only since I've switched to TP2, where when I want to fade a song out via the volume mixer on say, track A&B, it will cut the volume, even though I've only moved the fader down one notch, and the LED display changes from [ON AIR] to [SAMPLES]. How do I get it back to where the volume faders should act as they should. Surely, there is something I have changed? Thank you for your imput, I didn't get any responses from the official NI community