Can you take those pictures again on a cloudy day? Or in the shade? What it looks like to me is a disease from overwatering. Have you been watering more frequently than once every 3-4 weeks this spring? With temps in the 90s you should be watering once per week, so seeding the new grass into old grass is a balancing act. Can you get close (3 inches) and take another one in the same area as the second one again?

Or it could be the new grass is succumbing to the summer heat. New grass almost always succumbs to summer heat, so this does not really surprise me. It happens every year, and we tell everyone we can, that fall is the best time to seed northern lawn grass.

I'd use some more fertilizer if I were you. The heat can definitely do a number on the grass too though.

I think it's a lost cause. You keep watering every 4-6 hours you're going to germinate every weed known to man. If your water is free then you can keep trying, if not you should cut your losses and prepare for fall seeding.

Water is free and Scotts starter fertilizer with crabgrass preventer has done a great job at keeping the weeds in check. I will try to get another picture

Keep in mind that the pre-emergent will only last 5-6 weeks. Sounds like you're getting close.

I seeded in April (17) against common convention (smaller area). Tenacity was great to keep weeds at bay, same AI in Scott's starter with weed ontrol. But at this point you should be watering once a day, you could be overwatering 10 week old grass. Even in the 90s I did once a day. Also when did you drop starter fert last? Drop some Milorganite too.