You find it surprising that an American author and book editor don't read or speak German?
I'm guessing the author remembered the word incorrectly and wrote it down that way. It's not hard to transpose two letters when you don't know the language.
The book is really well researched, it includes 5 pages of selected bibliography. I doubt the author wrote about a scientist coining a word and then recalled said word from memory. There's no misspelling of the word "Entscheidungsproblem" which occurs like 80 times. It just stuck out to me, maybe the source material was already wrong, maybe he was trying to be funny or nerd snipe someone, it's a mystery.
I'm guessing the author remembered the word incorrectly and wrote it down that way. It's not hard to transpose two letters when you don't know the language.