If the absence of flaw in beauty is itself a flaw, then beauty is actually flawed, and the statement no longer makes sense.
Or in other words, something cannot both be absent of flaws yet flawed.
In my opinion it's a misunderstanding of beauty and flaws - someone is still perfectly beautiful despite their flaws (and in a way their flaws can allow it to shine through), which simply means that they are inherently beautiful, and their beauty is flawless to the point that all *other* flaws no longer matter.
(Sorry, I just had to do this - I'm really picky about such things :P)