Tabular and Normalize Query

Hi, I was using Normalize in the tabular process and trying to emulate the RossMann exercise with a dataset of my own. I got a problem and investigation showed that the routine was tring to run a normalize from the matlib color library rather than Fastai. The Rossmann version was fine. Is it my data that is causing this error? I have since excluded the option and used my own normalisation routine.

Anyone had a similar issue?