"Walker's Carnivores of the World" is a 2006 re-release of the carnivore chapters from the 1999 (sixth) edition of “Walker's Mammals of the World”, edited and updated to some degree, which states the same in this regard as the excerpts you mention from the main work - these references being what I was thinking of.
Chatting about feline taxonomy is always fun, but it is also important to point out just what a lovely photo this is.
