Paper can become wavy or bubbly because of it has absorbed moisture from being in a high humidity environment or being stored on its side. If you store rolls of paper on a hanger remember to rotate the rolls at least once a week. If it is used/stored on a rod the paper can develop wrinkles if the rod sags.
The best way to store paper is in its box and standing on end. To use it place the box on the floor, pull the paper out, and tape it to the wall. Roll it back up and store it in the box again when finished.
Living and loving it in Bangkok, Thailand. Canon 7D - See the gear list for the rest.