Widescreen bars / White lines during playback

[robf26216684]

I was wondering if anyone could help me figure out what's going on here. I just got a new mac pro, and all of a sudden, when I place widescreen bars (PNG file created in photoshop) into a 1920x1080 timeline, whenever I hit the playback button, there is a white line of pixels at the edge of my widescreen bars (see attached). As soon as the video stops playing, the white lines go away. The lines also do not show up in my renders. Any ideas why they show up during playback?

[Dp989]

Had this happen as well. I think it happens if the black bars png file is not the exact same dimentions as your sequence.