I've seen cases where the bees where in the upper deep and did not move back down to the bottom, where there where still stores, and starved to death. I have not had this happen
To me it has happened many times. It happens too that the ball start from middle and move to another side. Another side has food, but when it is very cold, bees do not know and they cannot move onto food, because "they have not plan and they do not know".
That is why long ,strong frost periods is difficult to bees because on their site food will be finish.
During a warm period ball expands and will meet the edge of food store.
One gap of bees may too die if food is consumed to finish in that gap. Bees drop to bottom board.
Small colony is in a danger if it has ball in the middle of combs. They will not drill a hole through the comb.
But this happens mostly in late winter.