Llamas do not show colour of rug

I had llamas in my world with all of the different coloured rugs. Now they have all reverted back to a normal trader llamer look even though they are wearing a coloured rug. Any new llamas that I tame and put a rug on do not change from the trader llama look.

It appears that it is only this world that I am having issues with, and I also keep this world on a Realm, where the same issue applies.