The US is keen that their proxy forces of the SDF have the honor of capturing Raqqa rather than the Syrian Army and that this new US troop deployment didn’t come as a big surprise and might not stop there.
In the end, the US wants a part of the cake. It wants leverage that can only be achieved by considerable troop presence.
Yet, there is no possible way that this deployment was not coordinated with the Syrian Arab Army and government as well as with the Russians acting as intermediaries.