findall doesn't find axes object

I have an app that creates a TabGroup and inside it some tabs that contain a plot. If the specific tab exists, I would like to plot on top of the existing plot. However, when using findall to find the axes that were created but I get a 0×0 empty GraphicsPlaceholder array. What am I missing?

tabs = get(TabGroup,'Children');
tab_names = arrayfun(@(tab) tab.Title,tabs,'UniformOutput',false);

if (~ismember('Station',tab_names))
    station_tab = uitab(TabGroup,'Title','Station');
    station_tab.Tag = "Station";
    station_tab.AutoResizeChildren = 'off';
    
    station_ax_Tt = subplot(2,1,1,'Parent',station_tab);
    station_ax_Tt.Tag = "ax_Tt";
    
    station_ax_Pt = subplot(2,1,2,'Parent',station_tab);
    station_ax_Pt.Tag = "ax_Pt";
    
    plot_stations(station_tab,station_ax_Tt,Tt,station_ax_Pt,Pt,Nm);
else
    station_tab = findall(groot,'Tag',"Station");
    station_ax_Tt = findall(groot,'Tag', "ax_Tt");
    station_ax_Pt = findall(groot,'Tag', "ax_Pt");
    
    plot_stations(station_tab,station_ax_Tt,Tt,station_ax_Pt,Pt,Nm);
end