Did a similar job to Dereks a week ago.............fridge left open over the weekend and flooded a small area of an office with accompanying smell.
That job was extracted, sprayed with an enzyme product and rinsed clear of odours and left clean.
This " smelly job "was, on the face of it, a straightforward clean of a longish but dense synthetic pile twist, which if constructed properly should have presented no problem.
Because it was a " clean " carpet and there was a requirement for quick drying there was a low volume of water and the psi was down at 150 max.
Having cleaned loads of B/W's without mishap there was never the slightest expectation of a problem with this type carpet and with the very small amount of water reaching the base of the pile it's astonishing that a chemical reaction appears to have taken place and worse still........there is no known solution to the problem.
Customer has been informed of my discussion with the retailer and my efforts to find a solution from within the industry. I've suggested she contacts the retailer.