So I found this in another bag full of international coins and I'm having a hard time telling if this is am error or not. The date looks like 1000 when there is little to moderate light and when there is a lot of light it looks like 1999. I'm assuming it's 1999 but is this an error?
No error. It just looks to me like the toning on the coin makes the bottom part of all the 9's harder to see. That explains why you can see the date clearly in the last photo.