generative fill very pixelated at large poster dimensions

Maybe not a "bug" per se, but I used generative fill for the top 1/3 of what's in view in this screenshot. As you can see the bottom 2/3 has very sharp defined lines but the top 1/3 looks like have enlarged the image beyond what's acceptable but I havne't enlarged it at all. I did do the generate fill while zoomed out to be able to see the entire image but that's it 🤷‍♂