Brown Striping in Fescue?

[monster8]

Hello all, got a situation with which I'm not sure how to handle. Mowed customers lawn a week ago got these pix in email today... she says started looking like this a day after I was there.

Front yard is looking good but backyard has this striping. Any clues as to what is happening.

Trugreen was there about 3 weeks ago but I don't think that matters.
Mowed with Walker GHS, 42" mulching deck about 3 1/2".

Almost looks like needs more water but wanted to eliminate me and the mower as the problem first.

http://i781.photobucket.com/albums/yy97/MarcusStefan/DSC00593.jpg
http://i781.photobucket.com/albums/yy97/MarcusStefan/DSC00592.jpg

[RigglePLC]

Looks like "Heat Tracks"
http://www.ipm.msu.edu/cat08land/l07-25-08.htm#5

A rather mysterious problem. No one knows for sure, but probably due to mowing grass that is just at the wilting point. Tire tracks show up. Even footprints sometimes. It will recover in about 3 weeks. Nothing you can do now. A fertilizer treatment might encourage it to recover about 25 percent quicker.

[monster8]

Wow!!!! Good info there.
Thanks