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);