The most obvious answer must be "because your string is being interpolated". The "@yahoo" part is being interpreted as an array, which is undefined. If you "use strict" it will confirm this.

($_='kkvvttuu bbooppuuiiffss qqffssmm iibbddllffss')
=~y~b-v~a-z~s; print

In reply to Re: parsing CDATA with XML Twig by Cody Pendant
in thread parsing CDATA with XML Twig by Anonymous Monk

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