Following translations confuses our JIRA-user:
When you 'create' an new item then you can select in the fields 'Komonente' (=Components), 'Betrifft Version(en)' (=affected Version(s)) and 'Umsetzung geplant in Version' the value 'unbekannt' (unknown). The user interprete this value as a 'real' value (that they really on't know the right value) and not as a kept free attribute! Other fields like custom fields displayes instead the option 'none' (unfortunately not yet translated in German!!) when they don't select any value for a field! What the confusion increase is that in the items detail view the value 'keine' (none) is displayed instead of 'unbekannt'.

May be this is not only a German translation problem! I guess this is a general issue in all languages (as well in English with 'none' and 'unknown').