Dark Brown Spots Grass
I am new to lawn care as I purchased my first home in late Fall last year. At the time, the grass was quite beautiful and all the neighbors loved it. Winter came not too long after and it went dormant, eventually turning a light brown like everyone else's grass, so I think that is expected.
However, today I noticed several darker brown spots in it and am not sure what it is. Disease? Dead? They are all smaller but somewhat in the same area.
It is Meyers Zoysia grass in Atlanta. Temperatures havent been terribly cold although there have been some colder days lately (for Atlanta...). When it was still growing in fall, I mowed it regularly to the tallest recommended height (2.5 inches maybe?). Right before Winter, I put winterized with fertilizer (new to that too, although I didnt notice any issues at the time so think it turned out ok). Also used to water it with irrigation system using same settings previous owners have for years. Note that I have since cut it off for the last couple months or so since it is winter and dormant - is this ok? I never see other people watering in Winter. Now its currently in the 40s at night so I dont think it would freeze, but dont know if its necessary. I also poked at the ground and it isn't hard so seems soft enough.
Does anyone have any idea what this may be? I did not see it in other yards. Most of them have landscapers, and the prior owners did as well, but I am more of a DIY kind of guy and feel like I should at least start off caring for my first lawn.