Hi Christine,
yes i've had this problem along with what i call stripping a grear shift or clutch. It sounds much louder than normal stitching when it is doing it ..and it seems to skip a stitch at the same time. ( i can actually feel a difference in the hand control when it's doing this) Odd thing is it only does this when using the encoder mode.
i have a repairman on the way this week. have yet to have the bottom of my quilt stitch right no matter what i change. the top still looks pretty good.
Can't wait to get it fixed and get on with quilting!
Good Luck