The same thing has happened to me. It just stayed in first gear, bouncing off the rev limiter. I'm pretty sure I hadn't accidentally touched the paddle, but I couldn't say absolutely that I didn't. So when it wouldn't upshift on it's own, I did try to upshift via the paddle which didn't work either. So I pulled over, selected the transmission selector to the left/paddle and then back to the right/automatic, which cured the problem.
As far as it happening again, it's never done that since (staying in first gear), but has stuck in a higher gear, necessitating moving the lever/selector to paddle and then back to automatic. Again, I don't think I accidentally touched a paddle to initiate the whole thing, but I can't be positive.