Croatia media are reporting that the local German embassy had the German Air Force fly a Eurofighter from Germany to Croatia to deliver a case of mustard. This was all in support of an embassy event, which was holding a 60th anniversary celebration of the German democracy, and were unable to find the special mustard that is traditionally used on some of the German sausages being served.
The media is pushing this as some kind of scandal, but military aircraft have always done double duty when flying training missions. Military transports regularly carry passengers, and cargo, between bases when they are mainly flying for training purposes. It's less common, but not unknown, for fighters to carry some vital bit of cargo on a training mission. This sort of thing only becomes an issue if the crews, who are often reservists, are carrying people or cargo for personal gain. That sort of freelancing is a no-no. But otherwise, doing double duty is considered, well, efficient.