Using plotly.express (px) to plot a Histogram with barnorm = 'percent' and marginal = 'histogram' produces a plot where the barnorm is ignored and the raw counts are plotted. I think the output should be a histogram with barnorm = 'percent' and a marginal histogram with the regular counts.

px.histogram(pd.DataFrame({'x': np.random.normal(0, 1, 100),
                           'col': np.random.choice(['A', 'B'], 100)}), 
             x='x', color='col', barnorm='percent', marginal='histogram')