Just got back from a week vacation and I have a bunch of dormant patches that weren't there when I left. It's been almost two weeks since I've mowed and we've had a lot of rain. Is it possible that the grass is too high and is choking itself out?

Other possibly relevant info:
1)I sprayed for crabgrass three weeks ago with MSMA, but I only spot treated, and not in this spot.
2)I overseeded a year ago and had similar patches from burning the grass with too much nitrogen. Those patches greened up in the late fall/winter, then came back again in the spring. They're now fairly green, with a few small dead areas.