I have seen similar effects when final washing both (120) Velvia and Kodak Portra films, but it doesn't seem to do any harm. Given the complex nature of film emulsions it is inevitable that something will be water soluble enough to show up in the final wash.

OTOH I tried pre-washing Portra on one occasion, and the wash water came out thick and green.

It didn't seem to do much good for the colour balance either.