I've just discovered a strange bug in DVDpedia. I was copying the info from the Date Added field to the empty Last seen field on several hundred movies. When I was finished I discovered that many fields had gotten a wrong date. Because I had a large amount of fields, I was able to see a system in the errors.
Only movies added in May and October turned wrong. They kept the same date number, but the month turned to November instead. If a movie was added for example Oct 6th 2006 it turned to Nov 6th 2006; a movie added 15th May 2005 turned to 15th Nov 2005. It is enough to double click in the Date Added field and press enter again, without re-entering anything. The date always change. But only for movies added in May and October.
May and October are the only months where the three first letters are different from my language (Norwegian: "mai" and "oktober"). Maybe this is a leading thread, but I am not sure. And I guess that if I did this in for example December, they would have turned to December and not November.
Wrong date when editing Date Added
Apple only knows the short months name in English and not Norwegian. It is a bug; but it is a bug with Apple. I will post a bug report with Apple about this. The reason November comes up, is because if it doesn't understand the month "Mai" it assumes the current month. The solution for now is to write the month in numbers 05/06/2006. Because you were copying from a DVDpedia field you can change the date display preferences in DVDpedia to copy and then change them back.