Most Lewisville yards sit on black clay. In a wet spring the soil swells and a head that was flush in March sits high enough for the mower. By August the same clay, the Austin Chalk and Eagle Ford ground under the inland neighborhoods, shrinks. A gap opens around the body. The head leans. The nozzle that used to land mid-lawn stripes the sidewalk.
That lean is a head repair, and often a swing-joint repair. The funny pipe takes the bend until it kinks. A new nozzle on the old tilt still leaves the yard. On a startup the height is set after the zone has run, not while the soil is still soft from the leak that brought the truck.
The lake side does this less. Sandier pockets toward Lake Lewisville drain, the heads stay put, and the failure is grit in the nozzle instead of heave. A cocked head after a month of heat is a different truck stock than a valve that will not open. Say which one you see.
The same shrink-swell cycle is why a leak in a foundation bed matters here. Water held against the brick is not only a water bill. If the wet spot is at the foundation and the heads look straight, start with leak repair rather than a bag of nozzles.
Call (940) 239-0007 if a head is spraying the walk or sitting above the grass. The wider visit is head repair.