Does the game know about different declensions needed for different purposes in German (and other languages as well)? In English, different forms are used for singular/plural, otherwise they are the same (my limited amount of English grammer may make me look like a fool now).
"This is a wine merchant", "I talk to a wine merchant", "I play a Wine Merchant"
all use the same phrase in english: "a wine merchant". In German, these require different declensions, mostly recognizable in the form of "ein":
"Das ist ein Weinhändler" (Nominativ), "Ich rede mit einem Weinhändler" (Dativ), "Ich spiele einen Weinhändler" (Akkusativ).
Most actions in Dominion use the Akkusativ in German (play,draw,gain), and many of the corrections we see in this thread show this. But in a few cases the Nominativ must be used. In a recent game in the end screen there was a card listed in the detailed VP list as "einen Weinhändler" (which would be Akkusativ of Wine Merchant), when it should have been "ein Weinhändler" (Nominativ).
If the distinction between those cases (Nominativ/Akkusativ) is not made in the code, it will always be wrong one way or the other. Since most of the time Akkusativ is used, which in many case is the same as Nominativ, this doesn't show very often.