I did a carpet in my first year of trading, it was a dining hall of an officers mess, approx 20m x 20m !!
As I was nearing the end of the clean I could see the areas that I had done first bubbling up to a height of about 6" off the ground, I was sh!tting myself.
Just then the Mess Manager came in and asked if that was normal, I bullsh!tted and explained that it was air trapped under the carpet and it would settle down when dry, he walked away happy and it did just that...............luckily!
We did all the other carpets in the mess, bedrooms, conference rooms, corridors, all exactly the same carpet but the dining room was the only one that bubbled.
Does anyone understand what causes it?