When starting a saved world the my tame llamas (2 llamas and one trader llama) started spitting at sitting, tamed dogs. This aggro'd all of the dogs causing much bloodshed. I reloaded the world from backup and separated them in case something else caused the llama aggro and the dog just got in the way. As soon as they got close to each other again the llamas started attacking the dogs again.

I started another world in creative and tamed 2 llamas and a trader llama with the same result. And again with just llamas (no trader llama). Same result.

 In survival and in creative tame llamas are always aggro'd against tame dogs without provocation.