I've got a SCX-5935FN whose DADF runs for a couple of seconds longer than it should when feeding a letter-size document (and yes, it sees the doc. as letter-size). This results in a noise as the feed roller continues to turn & rubs against the sep. pad. With multiple docs, this results in the 2nd doc. feeding in immediately on the heels of the 1st and resulting in a jam. I'm sure I've seen this before, but don't remember the fix & didn't document it.