Im masking out a word in a sentence and moving the word to the right side of the screen. Should be a VERY basic setup and it looks fine in the workspace and on RAM preview. But when i render the movie the mask won't keep up with the moving word. It cuts the right side of the word and reveals some of the other words on the left. Kind of drags its feets.
Any idea whats causing this? It it a common problem?
It sounds like a motion blur problem -- try turning it off for the layer. This happens usually because motion blur is turned off for the composition during RAM Preview, but turns on at render time when you select 'Best Quality'.