Imported video sequence flickers

Has anyone experienced flickering when importing video sequences into the viewport/camera? I’m using the official 2.56 and it seem to affect both image and video sequences, no matter the format. However, when I play through the entire sequence in Blender the flickering disappears (for a moment at least), which leads me to believe it could be a problem with the cache, though I’m not certain.

Has anyone experienced this before, and is there a fix?