It is perfectly normal.
When the seamless is on the roll it's perfectly smooth. I've never seen anything come off the roll that is less than perfect.
However, when you leave the paper unrolled and it's exposed to changing temperatures and the environment it will develop those buckles and wrinkles. If you let it hang loosely it's unavoidable. If you leave it rolled down to the floor with the sweep it will happen. If you let it hang without touching to floor and have clips or weights at the bottom then it keeps it pulled tight and it shouldn't happen.
If you're rendering it as pure white then it doesn't show up but anything less than pure white and you'll see it.
The way to avoid it (too late for the paper already affected) is to roll the paper back up when not in use.
As far as a fix goes.... not possible. You can either use the part that's affected for pure white shooting or cut it off and start with a fresh piece of seamless.