there is no listing for a 1989D DD but I found this coin the other night and it looks like there are two 8's in the date one right over the other.
It looks like the copper clad plating is what caused this one. but I am no expert. maybe someone can explain it better.
There is heavy die deterioration going on with this coin, and this causes die-deterioration doubling. The most famous example is the 1955 "poor man's double die." You can read about these forms of "doubling" here: http://www.errorvariety.com/OFD/DDD.html
Thank you for the info I knew it wasn't a double die. but it didn't look like most of the other machine doubling I had seen.