AppDesigner: bar graph behaves differently when using breakpoints

Hi all. I'm having an odd issue with MATLAB. I'm using AppDesigner to analyze an Excel Spreadsheet and display the results on screen. The output figure has two axes, one of which is a bar graph, and the other of which is a line graph which is used to summarize certain of the bar graph results:

This is what this graph is supposed to look like. It's what the graph does look like if I set a breakpoint before the line graph is plotted. However, if I run it straight through without any breakpoints (or with a breakpoint after the line is plotted), this is what it looks like:

What appears to happen is that the bar graph suddenly ignores the "grouped" setting and instead displays as if it were three sets of data plotted concurrently. You can get the same output by turning on 'hold' and running three different bar functions. Oddly enough, this behavior occurs if I place the breakpoint directly in front of the relevant "plot" command, before the plot command is even called. This appears to be independent of the code entered directly before the plot command. Update: the previous statement is wrong. This behavior does appear to be linked to the yyaxis command, and not the plot command.

Any ideas about what could be causing this? I'll post the relevant portion of the code, which is rather lengthy.

function PlotButtonPushed(app, event)
            app.PCBlist = [];
            app.actions = [];
            app.daynum = [];
            yyaxis(app.UIAxes,'right');
            cla(app.UIAxes);
            yyaxis(app.UIAxes,'left');
            cla(app.UIAxes);
            legend(app.UIAxes,'off');
            app.regraph;
end

function regraph(app)
            
             % Several try/catch error catching functions.
                   
             switch app.DataDivs.Value
                 case 'Years'
                     datintv = calyears(1);
                     formatout = 'mmm yyyy';
                 case 'Quarters'
                     datintv = calmonths(3);
                     formatout = 'dd mmm yy';
                 case 'Months'
                     datintv = calmonths(1);
                     formatout = 'dd mmm yy';
                 case 'Weeks'
                     datintv = caldays(7);
                     formatout = 'dd mmm yy';
                 case 'Days'
                     datintv = caldays(1);
                     formatout = 'dd mmm yy';
                 case 'Hours'
                     datintv = hours(1);
                     formatout = 'mmm dd HH:MM';
                 case 'Minutes'
                     datintv = minutes(1);
                     formatout = 'mmm dd HH:MM';
                 otherwise
                     datintv = abs(date_d - app.daynum(1))/10;
                     formatout = 'mm/dd/yy HH:MM';
             end
             if date_d < datend
                 app.daynum = date_d:datintv:datend;
             else
                 app.daynum = datend:datintv:date_d;
             end
             app.daynum.TimeZone = 'America/Los_Angeles';
             
             yyaxis(app.UIAxes,'left');
             app.UIAxes.ColorOrder = lines();
             app.UIAxes.NextPlot = 'add';

             switch app.Dropgraph.Value
                case 'Bar Graph'
                    app.reactbar(formatout,false);
                case 'Line Graph'
                    app.reactline(formatout);
                case 'Stacked Bar'
                    app.reactbar(formatout,true);
             end
             
             app.ResultsTable.Data = num2cell(app.actions);
             app.ResultsTable.ColumnName = app.PCBlist;
             for idx = 1:length(app.daynum)-1
                rowname(idx) = strcat(cellstr(app.daynum(idx)), '–', cellstr(app.daynum(idx+1)));
             end
             
             if app.AverageSwitchingActionsCheckBox.Value
                app.allswitch; 
             end
             if app.AverageReactorActionsCheckBox.Value
                app.allreact; 
             end
             if app.AverageCapActionsCheckBox.Value
                app.allcap; 
             end

             app.ResultsTable.RowName = rowname;
end

function reactbar(app,formatout,stacked)
            if stacked
                stackout = 'stacked';
            else
                stackout = 'grouped';
            end

            [~,PCBs] = app.elemlist; 
            
            for idx = 2:length(app.daynum)
                for jdx = 1:length(app.PCBlist)
                    app.actions(idx-1,jdx) = sum(isbetween(app.datatable.Time(PCBs(jdx,:)),app.daynum(idx-1),app.daynum(idx)));
                end
            end
            
            if ~isempty(app.actions)
                bar(app.UIAxes,app.actions,stackout);
            else
                return
            end
            
            if stacked
                yax = 1.2 * max(sum(app.actions));
            else
                yax = 1.2 * max(max(app.actions));
            end
                 
             app.graphformat(formatout, yax);
end

function allswitch(app)
            totacts = mean(app.actions,2);          
            yyaxis(app.UIAxes,'right');
            plot(app.UIAxes, totacts);
            app.UIAxes.YAxis(end).Limits = app.UIAxes.YAxis(1).Limits;
            app.UIAxes.Legend.String(end) = {'Ave. Switch Actions'};
end