That's bizarre!

@mayflowerlash, I wonder whether possibly it's to do with an eBay script trying to filter out misuse of the word "not" in titles and descriptions. (Keyword misuse, as when someone tries to list a jacket and, in order to attract people using the word "Chanel", the seller states "Not Chanel" in the title, description, or both.)

At any rate, what you describe seems either like a temporary technical glitch, or something gone mad in a bot-generated script.