wrong yticklabels after setting yticks using set(gca...) and changing font size

I have found a strange behavior when setting yticklabels:
I wanted to display my yticklables in % and used the following code:

yt = get(gca,'yticklabel'); % original yticks: eg [0 0.1 0.2 0.3 0.4]
set(gca,'yticklabel',...
         num2str(100*str2num(yt),...
        '%-1d%%'));
                                                                                   % alter yticks by multiple of 100
                                                                                    % now [0 10 20 30 40]
                                                                               
This works well.
However, if I later on would like to increase the fontsize of the yticks, the resulting plot is displaying a wrong y-aksis! Eg.:

set(gca,'yticklabel',...
         num2str(100*str2num(yt),...
        '%-1d%%') ,'Fontsize',14);

It seems as if only the that part of the ytick vector, which is visible with the increased font size, is displayed. However, THE POSSITION of the ticks is now wrong! Eg. '10%' is not displayed, instead is '20%' is now displayed AT THE POSITION where the '0.1' ytickmark was earlier displayed!

Is this a Matlab bug or do I oversee something here? Your comments are much appreciated!
version = 8.3.0.532 (R2014a)