Issues when plotting stacked and non-stacked bar graphs on same figure

[xarico10]

Not possible to plot stacked and non-stacked bar graphs on same figure:

y = [1 2 3; 4 5 6];
tiledlayout(2,1)

% Top bar graph
ax1 = nexttile;
bar(ax1,y)

% Bottom bar graph
ax2 = nexttile;
bar(ax2,y,'stacked')

fig2plotly();

Expected and generated (https://chart-studio.plotly.com/~xarico10/561/#/) plots:

As seen, one of the graphs shouldn't be stacked, however both are. Also, there are color mismatches.

Examples on this type of practices can be found on:
https://www.mathworks.com/help/matlab/ref/bar.html#btj3klf