I did some research on this and it appears to be an ink transfer/offset error. What do you guys think?
That's precisely what you have. Nice condition too. This type of error occurs when a sheet does not make it all the way into the press. The printing plate and impression cylinder make contact, and the ink is transferred to the cylinder. When the next sheet goes in, the cylinder makes the impression of the opposite side onto the paper. This occurs until the ink is used up. Because the offset is light, this is probably not the first sheet to the get the offset error. However, due to the condition, you've got a nice keeper.
As funkee has mentioned the Off-Set errors come in different levels of off set (ink transfer shades). Here you can see that this note was in the top 2 or 3 if not the 1st off the press..(very dark) enjoy the "Ghost"..Off set's are a great choice for error note collectors.
