Wagers are made after the category is shown but before the the clue is revealed. It can only use the confidence in its knowledge of the category, not of the question itself, in the calculation of the bet.
Ah, didn’t know this. Sorry, there has been no Jeopardy on German TV since I have been 12, it was not really clear when the wagers are placed. Well, makes sense. I guess they are very nervous about FJ! and know that it’s not one of Watson’s strengths.