is there a nice tight fit between top and bottom sections ? If not the mast can kink rather than bend smoothly making the crease worse. If its loose, apply some tape to the top section plugs so its tighter.
I also have this crease. Pretty new standard sail. I re-did the tape packing between the two sections the other day to make sure that was not the cause (i.e. they are decently tight now). Crease runs between th e joint between the two mast sections and the clew.
Just ignore it or am I setting the sail wrong or badly ?
in lighter winds you want that "speed wrinkle" it means your sail is fuller to make this speed wrinkle you shood have no hammy on it will make you go alot faster.In heavier winds you want the hammy on to make that wrinkle go away