Fletcherism. And here's another random thought to ruminate on: What, if anything, is the connection between cud and cuddle? Answer: there is none, except that while women typically want to "cuddle" after making love, men often prefer to pick up chewing where they left off. (Just cudding!) There were 62 cases of Incud* found in OhioLINK this morning, and 1365 in WorldCat. Chew on today's typo for a little while and see how many you can include in your own list of corrections.
(Cow portrait, 29 May 2005, from Wikimedia Commons.)