Distortion can be caused by leaving a kayak on its "soft underbelly" for long periods. You can dent the bottom. The boat will naturally heal to one side and possibly cause uneven loads on the belly and, over time, cause it to invert "dent".
You can create a cradle that helps support the boat on the "shelves" on either side of the belly. Perhaps two boards lengthwise and slide the boat onto them so the belly is off the ground?
Director of Parts and Accessory Sales
Hobie Cat USA