Crossing breeds effect on dogs appearance

You know when you go to breeding dogs there are things back in the wood pile that show up some times, I seen some grade ol country breed walkers once that had about 1/8 or 1/16 plott hound back in there and every once in a while when bred either line bred or out crossed out they threw a partial brindle pup. I remember seeing some yella dogs on here maybe skoals or Big o's can't remember that were throwing dogs with a little longer hair than what is commonly seen in ybmc dogs. What ever is in there bubbles up from time to time. It's like the hancoc.k horses from the broken bones ranch in wyoming, the throw patches of white and can't seem to get rid of it, some where a paint was probably bred in that line and that trait becames fixed some how and it keeps cropping up, even when solid roan horses are bred together.