Creased sheets rear edge operator side

Hi, Wondering if anyone can help??
We have 2 Heildelberg Presses Cd74 & XL75, on both presses we occasionally come across creased sheets on the operator side only & only at the rear of sheet see attached picture. Any help on this matter would be greatly appreciated, Thanks.

 

If your grippers are set right , i would say you should look at the air blowers on the transfers

 

it looks like it may be getting hung up in delivery because all the colors are printed on the color bars
check that your slowdowns are working or the blowdown bars

 

If the creased sheets aint in the pile (damaged stock) then i'd look at something catching the sheet mid unit.

As the sheet Isnt printed correctly to me and tell the photographer not to give up his day job