I have also just started encountering issues importing TIF files w/ alpha channels. Have been doing it for years into FCP. What changed for me is I upgraded Photoshop from CS to CS5. The files exported from CS5 no longer import into FCP, but if I open the same Photoshop file in CS and export the same TIF, FCP is happy. Any clues as to why this has become an issue? What is CS5 doing that is different? I confirmed it is an 8 bit TIF. I’ve tried RGB and Grayscale modes.