Might be an idea NOT to use the same cleaning product you used when the problem occurred

Sounds like it may have been an old bottle that you had in the back of the shed, so it could be past its best. You've already had some pretty good advice above.
What I'd do is bang some air movers in there ASAP to dry it off, then re-clean with M-Power (other colloids are available

) with an odour neutraliser in the pre-spray too. Give it a generous application and a long dwell, 30 minutes or more. Then thoroughly extract with hot plain water and stay on site with air movers until it's touch dry.
It's pretty likely this is caused by excess moisture, but the actual symptoms could be bacterial or the smell from the materials in the carpet's backing. Either way around (and I'm not wagging my finger here) to be honest you shouldn't encounter these problems because you should get carpets back to touch-dry or thereabouts before you leave the job.
Definitely one to learn a lesson from. Hopefully it hasn't delaminated whilst it was wet
