Well this is weird. I checked the tabs and nothing was there and so I tried re-exporting my video and it worked this time, no problem. *facepalm*
But one more question that is related to this same issue. I have added Fade transitions to some clips and I know those have to be rendered. However, after I render them, they too make everything, within the duration of the Fade, pixelated–even after Export. Does this have anything to do with the Shift Fields?