I was wondering this as well. Yesterday I did a free pull and it lit up as if I pulled a 3* ninja, and it ended up being 1 Jigokudo frag, which was still highlighted like 3 stars used to be...

Is this for real, was that a rare pull?

1% is a computer language thing, specifically it means the first argument supplied after the string (and for those of you don't know, string is what "text" is in computer programming)
Different coding language, however, have different ways of parsing things, and when parameters aren't properly supplied, behaves differently. So in this case, instead of the functional property that the 1% should have, it became a literal string that is printed out. In theory, this is only a display error, due to the way the string is rendered, and should not affect actual behavior (you still get however many fragment you should), but without knowing the root cause of the problem and/or any other change, I won't be able to be certain.