That looks like a herbicide or chemical burn to me

 

Something was split. What is behind the fence?

 

If not a spill, maybe heat coming off a generator test cycle?

 

There is a generator behind the fence, it actually turned on that day since power went out. But it’s hard to say because it kinda all happened at the same time. How quickly would it get like that if it was the heat?

 

It's new sod. It's incredibly sensitive. Overnight seems very plausible for a heat/exhaust injury. You can treat with a fungicide if you want, but I suspect you're going to find out the source of this problem is the generator. Either it's leaking or its exhaust isn't being diverted away from the grass. Hope that helps.

 

Bingo!

I bet 100 bucks the Generator is the cause.

 

Update. My pest control company went by and confirmed it wasn’t a fungus (they did a moisture test). He said it has to have been an issue with the generator exhaust.

I’ll be adding some rocks around it, every time the generator turnson it’ll hurt the grass.