After remuxing a movie with 2 sub streams, I was repositioning them (and re-doing the color which had changed) with Dvdsubedit. I didn't realize I should switch the preview to Letterbox, so I was manually changing the vertical distance (sometimes clicking "All modifications to all streams" when it looked right). I don't know if those changes might have anything to do with this problem, but the text looked fine up to this point
I figured out I had to change the preview window to properly align the text vertically; I used the vertical boundaries to raise the subs to the correct level. However, as I did this, I could see some subs in both streams have the tops slightly cut off, and this bit of sub is shunted (vertically) underneath the text. Played a sample and the cut-off text also vibrates slightly, too (like the dvd player is having a problem with it). Any way to fix this? Adjusting the vertical now doesn't change it, nor does adjusting the individual CLUT.