I found what I was thinking of! From Grant Brereton's '21st Century Poultry Breeding':
"... breeding a self Buff bird to a bird which doesn't carry any or all of the genes required for solid Buff, will in most cases result in Black tailed Buffs."
As I suspected, I was misremembering slightly. I imagined the bit about the black striped neck hackles, probably because I have a number of chicks from a Buff x Partridge mating who all turned out like that. They're very attractive birds IMO, even though they didn't turn out like I was wanting.
Also, I'm not sure what the difference is between self Buff and solid Buff.