Sheets Warping after Online coating

Hi,
My name is Ashwini.
we have been facing a lot of problems while online coating on our cd 74L. After printing the sheets tend to warp and develop waves due to which our hardbound books are not closing properly.
We have seen the same jobs being printed by other printers without these waves.
does anyone have an experience with this problem and possibly a solution ?

Thanks
Ashwini