Why do spots sometimes come back when I have my Carpet cleaned?

Carpet Stains reappeared in this Carpet!

It happens, the Carpet Cleaner leaves and a day or two later or perhaps a week or two and then a stain reappears.

3 Reasons Why Stains May Reappear.

Cleaning Too Fast: This is totally on the Technician. Sometimes a spot will reappear as soon as the carpet is dry. This is normally because the cleaner was moving the wand over the carpet too fast and the hot/steaming cleaning solution did not have time to flow down into the bottom of the carpets fibers before being sucked back into the suction stem of the wand, and out to the holding tank.  In other words he didn't go slow enough to get the dirt out of the carpet. He just got the tops of the carpets fibers. Therefore the dirt from the bottom part of the fiber came right back to the top of the carpet fibers as it dried. Otherwise known as Carpet Wicking. And surprise you still have the stain. Even though it was gone when the carpet was initially cleaned.