Very surprised this happen ! Didn't the crew felt anything while starting to taxi. With the truck still connected, this would request more power than usual, or maybe the truck was already disconnected but not yet left !
A B744, not at a very high gross weight, doesn't need power more than idle to start taxi. I rarely use power to start taxi on the B744, make so more safety behind, and in this case, it would in front for the ground staff and the material.