You AREN'T holding all three wood handles while pouring, ARE you? If so, that WILL cause the cavities to be apart. The top wood handle should not be grasped while pouring, it's only function is to start the swinging action of the sprue plate to shear the sprue from the base of the boolit.
That was the final solution to one casters problem similar to yours. He thought he had to grasp all three handles.
Otherwise, the above comments should be followed to determine what's causing the mold blocks to remain separated.
The more people I meet, the more I love my dog
They're going to get their butts kicked over there this election. How come people can't spell and use words correctly?