Heidelberg GTO form stripe?

I have a Heidelberg GTO, put in a brand new form roller (white) and
having trouble setting it correctly 2mm stripe to plate I can get 2mm on both ends
but most of the middle section of the plate is 4mm, never had this problem
usually it's the opposite as rollers swells on the ends.
pic attached

 

Back off roller from oscillator and plate fully, then adjust stripe to oscillator first then plate, perhaps you apply too much pressure on oscillator and roller tend to eggshape or check the length of roller with bearings, it could be longer and do bow. Also measure the thickness of roller from side to side and mid

 

It's time to change rollers now.