Are they English Cockers? Way back in the day (1970's - ) a particular pair of breeders was coming up with unusual colors in Cockers (allegedly American Cockers) ,chocolate (liver) chocolate and tan, sable, etc etc. No where was there a place in the breed standard allowing them but they persisted and people bought them like hot cakes.
Sadly the parents & pups etc. where not tested for PRA, familial cataracts, Hip dyplasia, a type of hemophila that certain lines, carried. On and on. Many folks got the color they wanted but also a host of very serious eye and health problems. Turned a lot of folks off American Cockers even though the serious breeders were still putting out sound/healthy, tested stock.
I'm sure the same could be said for many very popular dog breeds. The folks in it for $$$ and their 15 minutes of fame abound. While serious breeders work hard to keep quality & health up.