Clbuttic
More commonly known as the Scunthorpe problem, clbuttic is an issue that occurs with filters such as a spam filters that mistakenly blocks or denies something that is valid. The Scunthorpe problem derives from the swearword filter AOL was using in 1996 that blocked valid users who were living in this town from creating accounts from the obscene keyword found within this towns name. Clbuttic is an issue that occurs with a search and replace technique that replaces swearwords with valid words, in this case replacing "ass" with "butt" in the word "classic".
Today, both of these terms are used to describe any similar problem that is encountered with software filters or search and replace regular expressions.
Also see: Filter, Regular expression, Security definitions, Spam