The reason why "disfunctional" appears sometimes is likely due to:
* Mishearing: People might mishear the word and think it's "disfunctional" instead of "dysfunctional."
* Misspelling: People might misspell the word based on its sound or a misunderstanding of its etymology.
* Typo: Simple typos can also lead to the incorrect spelling.
It's important to note that the "dys-" prefix is common in words related to difficulty or impairment, such as "dyslexia" and "dyspepsia." This might contribute to the misconception that the word is "disfunctional."