Sprinkler head leaking.

I recently had sod replaced in my back yard. As the ground was being prepared the contractor destroyed a sprinkler head. He replaced it and laid the sod. I began watering regularly. The sod on the whole yard was initially soft but there was one area that was particularly soft. After about a month I noticed that the replaced sprinkler head continually ran after it shut off. An area of about 8’ to 10’ wide around that sprinkler head remained very soft. I had to turn the water off to stop the water from leaking.

I checked to see if there was debris keeping the value from closing and flushed the open valve. That didn’t stop the sprinkler head from leaking. I hired a sprinkler company to come out. They ended up replacing the entire valve unit. I let that dry for a day, turned on the sprinkler and it’s still leaking.

What else could you replace?
Is it just a coincidence the valve went bad when the sprinkler head was destroyed by a root cutter?
There has to be some reason that the ground within 8’ of sprinkler head continues to stay soft even though I don’t keep water running out of that sprinkler head.