FactorRange must specify a unique list of categorical factors for an axis: duplicate factors found

[yashinlin]

I'm using DataPrep for the first time using JupyterLab in my browser. I just tried running the line of code below

plot_missing(train0)

and I got the error in the title ("FactorRange must specify a unique list of categorical factors for an axis: duplicate factors found")

Earlier, I interpreted an "Error displaying widget" error as incompatibility with Jupyterlab 3.x.x, so I installed Jupyterlab 2.2.9 (source: https://discourse.jupyter.org/t/error-displaying-widget-model-not-found-how-to-fix-this/11886)

I think I was getting the error in the subject line before I downgraded my Jupyterlab version. I wondered if anyone might have some insight as to what might be going on? Thanks in advance