Variegated vanilla leaves completely lacking pigmentation

[AvantGardner]

Has anyone else encountered this? I have a cutting from the Missouri Botanical Garden's vanilla planifolia variegateata. A new branch is completely yellow, no green whatsoever. It is very slow growing and the leaves are small, maybe an inch and a half in length. I don't have a picture (posting pics is such a drawn out process with a slow Internet connection...). But the rest of the plant is growing in it's normal fashion. What's the deal? Mutation?