Could this be a very long zig zag? Since there is a pattern to the "jog" you might try resetting the stitch length and style and also the cleaning, etc. that yngldy suggested. I wouldn't take it to the dealer yet as I think this can be remedied if you reset everything. Give that a try and please let us know the result. I have a Brother and they are very similar if not basically the same and often resetting works.