I've got a Duplo DF-1200 that mostly does tri-folds. I've got a problem where every other sheet is folded wrong. This is a new issue as of about 2 weeks ago. We checked our front to back registration and it is almost dead on now. We use a duplo 618 to cut. We check those and adjust accordingly - so the sheets match each other as they are cut. Once it hits the folder all bets are off. We have cleaned the rollers and the sensors. Don't know what else to do. Could it be that the settings are bouncing around while it is folding? Thanks for any help you can provide.