On installing Lubuntu 12.10 I selected full disk encryption and was asked for a password. The password quality indicator on the right went from short to weak to fair to strong and then, as I typed an open bracket and another character, back to short --- despite showing about 20 masked characters at that point.

I ignored it, but when the install finish I couldn't get my password to work. This might be a coincidence, but I think the first issue here is definitely a bug.