No, its a sign your doing a good job. They are supposed to be "crinkled". Often when bought from the store this plant has been grown under emersed conditions and it doesn't grow the way it should submersed. The plant is supposed to grow its leaves close to the ground with short stems, they should be elongated, crinkled around the edges and depending on which kind of Wendtii, should be lightly brown or red.
This is a picture of my Red Wendtii immediately after I bought it (left).
This is a picture more like what it is now. If I didn't see it happen myself I wouldn't have believe this was the same plant.