german umlauts not stored correctly

[flashpixx]

If I write a document with the german umlauts "äüöß" it shows correctly until the first time if I save the document. After reopen the document it converts the "ü" for example to "Ăź".
But I check it, the error come into the document by storing the dataset, so imho Markdown is UTF-8 encoded, so this should be read / write correctly.