Help with my buffalo grass

So I posted this in lawn care but I think it’s a mainly American sub and got nothing. Hoping for some help here

I’ve got a buffalo lawn. It’s got timed irrigation. After manually core aerating the majority has come up beautifully. Top dressed, wetting agent, slow release fert all going strong. But I cannot fix these two patches. I had other similar patches which have cleared up and are growing over. I’ve done the same thing to these. I’m totally at a loss. They get plenty of water, as they’re beside sprinkler heads and the other problem areas got fixed.

I have no idea how to proceed.