Moses,
When the same area of a lawn has die-off problems year after year - with some recovery (usually fall-spring) - the problem can be traced to non-uniform application of water. While your irrigation system may LOOK like it is applying water uniformly, no irrigation system - no matter how new or expensive - will apply water completely uniformly.  My opinion (seeing these problems for 36 years now) is that you've got an application uniformity problem in this area. Further, if turf goes into winter drought-stressed, it is very susceptible to turfgrass mite injury this time of the year.

I suggest - when you irrigation system is back on - that you perform an irrigation audit of sorts, using the attached handout to guide you. 

Let me know if you have any questions or believe that I'm not understanding your lawn problem completely.

Thanks,
tony