https://project.lyndir.com/youtrack/issue/MP-12 For some reason, the x character class doesn't include all of the o class' symbols. I'm unsure why this is, but if there's no clear reason, we should probably consider fixing this by realigning the sets. This would be a compatibility breaking change so it would have to be postponed to an algorithm version change that affects all generated passwords (eg. a scrypt parameter bump).