Try switching papers, you are getting sheet distortion, it is very common. Think about what you did to that paper on the first pass through your press. You smashed the crap out of it, you hit it with four or five units of water, then you dried it out with the IR in your delivery.
You could try...
Run delivery loads no hotter than 100 degrees (US)
Reduce pressure to a minimum and double check plate to blanket pressure
Reduce water as much as possible
If you are coating, switch to a low curl coating
Check your infeed drum grippers and timing
Clean all gripper pads and check settings
If it is a Perfector, get it checked by a mechanic