How to get rid of this warning which point at extra entries?

Dear all, I want to know why do I receive the following warning if my code is not in a loop?

Warning: Ignoring extra legend entries.

> In legend>process_inputs (line 587)

In legend>make_legend (line 315)

In legend (line 259)

In PVGeo__SCy (line 394)

figure(1)
n=12;
U1=[energy_, (heat_cons + HDW_c)]; %%%Ren
U2=[(Power_ + Sp_ + Lamp_), (heat_cons_ + HDW_c)*SPF]; %%%Consumption
c{1}=deal(U1); 
c{2}=deal(U2);
b1= bar(c{1},'stacked');
b1(1).BarWidth = 0.4;
hold on;
b2=bar(c{2},'stacked');
b2(1).BarWidth = 0.9;
b2(1).FaceAlpha = 0.3;
% b2(1).BarWidth, b2(2).BarWidth, b2(3).BarWidth = 0.4;
set(b2, 'BarWidth', 0.9);
xlabel('Months', 'FontWeight','bold')
ylabel('Consumption vs RES (kWp)', 'FontWeight','bold')
grid on
xticklabels(LastName)
% go.Annotation.LegendInformation.IconDisplayStyle = 'on';
labels = {'Electricity consumption' 'Thermal consumption' 'Photovoltaic Generation' 'Geothermal Generation', 'Location', 'bestoutside' };
legend([b2 b1], labels);

NOTE:-

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Assuming [b2, b1] produces a vector with 4 handles, try this

legend([b2,b1], labels{:})

Or This

labels = {'Electricity consumption' 'Thermal consumption' 'Photovoltaic Generation' 'Geothermal Generation'};
legend([b2 b1], labels, 'Location', 'bestoutside');

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How to get rid of this warning which point at extra entries?

How to get rid of this warning which point at extra entries?