I had one a couple of months ago, that started rippling as I was pre spraying, advised the customer that it would be back to normal . also advised her to leave the patio doors open as there was a nice warm breeze coming straight in.
She phoned that night claiming the ripples were the size of a tsunami.
went back first thing the next day, and the same ripples were there, she confessed she didn't follow my advice. So I left an airmover with her, went back in the evening and everything was back to normal, She was pleased so much so that she recommended me to her friend who had the same carpet, she even warned her friend about the rippling and assured her that it would all go back, Cleaned her friends carpet and guess what............. it didn't ripple.