I had this exact same problem tonight on a PD-150. I have had this camera since 2002 (wow, that's 5 years) and have never had this problem. This has got to be a flourescent thing. In fact, I think our question has been answered in this thread consideringe the cycling of the lights. As soon as I switched to AWB it corrected itself. The one thing that is really strange that none of you have mentioned is that accompanying the color shift was a grinding noise when the color shifted to amber/orange. The sound came in a wave going from quiet to loud and then back again. I was shooting in a dance studio with probably 30 banks of cheap flourescent tubes. I'm glad I found this thread, I'm not so freaked out about it anymore. But, I sure hope it doesn't do it again.