different sizes of font in different submenues on mobile

On a computer the submenues looks fine but if I look through them on a mobile most of them still looks fine while others have a much largder font. e.g the titles under “Om” and “Ydelser” looks normal but if I look at titles under “Artikler” or “Metoder” subtitles differs from all others in beeing a much largder font size.
I know that the titles are longer and may not fit regardless but they still ought to be same font siza as the rest. Firther more I have tried just for the experiment to create a page with a short title, add it as submenu and that page ALSO has the same largde font. Anyone knows what′s wrong and how to fix it?