It also happens to me. No matter what codecs I use, it only occur (sometimes) when I do a Targa sequence, and only with the Mac.
I’ve just finished an animation, didn’t use any external files(nor videos,pictures), and it came out tinted in blue. Closed After Effects (Cs5), opened again, and…voilà ! A perfect TGA.
I really don’t understand it!! Same composition…sames files…seems AE is kidding me!