charset categories is odd

Hello,
I have an odd problem with my homepage, to be precise with my categories. As soon I change the title of my “Armbaender” category to “Armbänder” the page title, the category in the sidebar, the category below the products and the category in the menu in the header changes to “Armbänder”, although when I name the category “Armbaender”, the title on the frontend, the sidebar-category and the menu-category is “Armbänder”, but the category below the products is “Armbaender”. I suppose the problem is related to the charset, but I can’t find the problem. any help is highly appreciated.
Best regards,
David

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