If I understand the blog post correctly, the bug was in the software that creates (or maybe mounts? Not too clear about that) the encrypted volume. It needs to

If I understand the blog post correctly, the bug was in the software that creates (or maybe mounts? Not too clear about that) the encrypted volume. It needs to have the clear-text password in order to function. Then it proceeded to set the clear-text password as a password hint due to the bug.