^^ I am convinced that the scene with Obi-Wan was intentionally blown out that way.
If you notice, the part before Obi-Wan comes, which is in the same location, has normal colors.
It's precisely when Obi-Wan appears that the frame turns white.
For home video, they were probably trying to correct everything to "normal" and so they saw these blown out whites as a mistake and regraded it to match the part that had come before.