This is a function of the way Pro Tools and Media Composer treat fade-in and fade-outs. The entire region will be placed in sync to the picture. (eg. A clip in MC has a clip that has a fade-in centered on the cut, which is 8 frames in duration. In MC the cut point or transition is in the middle of the fade-in. When this is translated to Pro Tools, the fade-in will actually begin 4 frames earlier than the transition is in MC).