The explosions began as soon as the dropships cleared the energy barrier around the Pyramid. Whatever force had assembled themselves there was doing a magnificent job of it, but the persistence of the Arisen force didn't make sense.
They were taking huge losses, even by the standards of a ship that large, but they were still moving into the next phase and trying to send out their dropships to occupy the planet. It was nonsensical. Even if they could vanish at will, they presumably couldn't instantly replace all that they had lost, and they were just throwing away troops at this point.
They had to know that the ships weren't making it to the atmosphere intact, but they weren't slowing their attempts.
This whole thing felt off.