Drywall wrinkles?

[Airkings]

I'm painting newly installed drywall with Behr "new drywall" paint, which has been working great for a couple of rooms so far. For some reason now, on a small section above a door (about 2' X 1'), the drywall paper wrinkled or something, and now has ridges. It is visible from a few feet away.

What's going on here? Did I put too much paint on and the paper got wet? How can I fix it?

I thought about skimming it with a coat of mud, but I want to see if anyone has a better idea. I suppose it could flatten itself as it dries, but I doubt it.

Thanks in advance.

[Marvel]

[Norminn]

Was there a light or heat vent close to the "wrinkled" area? The surface of the paint may have dried too soon and caused the wrinkling, although it is difficult to visualize what is really going on. I would allow plenty of time to cure/dry, then try sanding and coating again.