For those who have watched the Mahiro Maeda interview, I'm pretty sure a good lot of you missing a fairly big chunk of subtitles. Rest assured, it does come back. However I haven't done any real testing. I first popped into my PS2 to watch it in my room. I then watched it out in the living room with a real DVD player, and then the subtitles seem to work all the way.
Just a little tip. It might be a PS2 problem, it may not. Either way, it looks like the problem lies in the reading of the disc.