Note the adjustment of the clearance of the roller after the BIG8 monobloc cutting heads is ELEMENTARY to prevent bow cuts!
Check if the roller is not “tilted” (and thus one-sided “in the air”), refer also to manual of your slitter how to adjust the roller.
Possible cause:
Check function of the reed sensors B256, B257, B258 and B259.
You can find them on the cylinders of the magnetic conveyor (Y125) and transport roll (Y124). Manually activate the two cylinders on the valve block and adjust the reed sensors if necessary.
Refer also to the pneumatic diagram here.