Downspout connected to underground perimeter drain tie

Brand new construction. Just two downspouts connected to drain tie, both daylight in the front yard. At the daylight points, both pipes had standing water. Blockage in the pipe? Incorrect slope of drain pipe perhaps? No standing water in gutters. I’m asking because every other time I’ve inspected these downspout-drain tie connections, there was never any standing water at the daylight points…even after a good rain. I guess they didn’t run the pipe far enough to daylight even with grade?

Possibly yes to both questions.

The pipe turns up at the end. Same issue as a sink drain trap, none.

The issue; how do you know they are connected to the perimeter drain? That would be wrong.