I have a DF-617 that's brand new and another one in the field, they are both having the same multi-feed issue! For example, using 20 one sided originals the feeder will pull two or more sheets at once without detecting a multi-feed or causing a jam when scanning to email. It would appear that the originals are stuck together and the machine cannot separate them. The rollers and separation pad are new and there is no obvious reason for the problem. Any ideas?