Take some close ups of the blades

 

 

I think you got red thread going on, all those purple blades and the rust colored one look like red thread to me.

 

I have never seen red thread be that dark.

 

The first picture shows spots with seed heads. Is this Poa annua?

Poa trivialis also thrives where Poa annua feels at home.

In summer or under stress due to drought, heat or herbicide, Triv often turns purple:

However, I find the even distribution and the similarly sized patches unusual for an infestation with Poa trivialis.

 

I’ve been reading a lot about this poa triv, and it’s common for it to die back in summer heat. I’m not saying what I have isn’t a fungus, but is it also possible if I have an infestation of this Triv grass that it died back during that hot day?

 

It could but my triv areas usually do not color like that.