I have an issue with the camper rocking back and forth constantly like the floor of the truck is warped or the camper floor is bowed but both are straight. All tiedowns have same torque load, i am using a rubber mat between the bed and camper as recommended by my bigfoot manufacturer.
Will rock back and forth with full or empty holding tank and gear is loaded from the front to the back also as recommended.
Is this an issue with a newer truck bed and an older camper design or is this a normal thing for a camper?
It is really annoying.
anyone else have a camper that bounces up and down along the road?

Two things come to mind:
1. Tires. I run load range E on SRW carrying a 3000 elkhorn and I do not have the rocking you describe.
2. Sway bar. Do you have one?

Also, is the camper floor approximately as wide as the distance between your wheel wells inside the box? If not, you could add a second wider plywood outer floor to your TC to give it more width. It could even get wider behind the wheel wells. Kinda hokey but it might help.

If the whole truck is rocking front to rear then I have heard that upgrading the truck's shocks to a heavier duty set of shocks helps. If its side to side rocking then airbags would help.

I have side to side rocking with my camper so I added the Torklift Stable Loads. These make use of the overload springs on the truck when the camper is loaded. They helped quite a bit but I think that the addition of airbags would help a lot more. I have a 1 ton dually truck and run E load rated tries all around. My camper weighs in at just over 3000lbs.

I also do see some front to rear rocking when travelling over some rougher roads. Usually slowing down a bit stops the rocking so it doesn't really bother me much. Adding a set of Rancho RS9000 XL shocks would probably cure this problem but I haven't tried it so I really can't say how well they would work.

I had a bed liner in my first ruck with camper and it was scary. I got rid of the liner and put down a sheet of plywood and that solved the problem. That was an older heavy camper.