2) Too much entrapped air. If consolidation was not sufficiently done, there might be still large amount of entrapped air voids in the already placed fresh concrete. Those air voids can be evacuated from the concrete especially through the boundary between the concrete and the surfaces of the formwork, causing the already placed concrete to settle.
3) Movement and deformation of formwork. Movement and deformation of formwork can also lead to settlement of the placed concrete and lead to settlement cracks.