Answer:
Yes, there was a mistake
Step-by-step explanation:
The mother is of type B blood whose genotype can be BB or BO
The father is of type AB blood whose genotype is AB
The baby is of type O blood whose genotype is OO
Thus, if the mother is of BB and the father AB, the can only produce children of AB and B bloodtype.
If the mother is of BO and the father AB, the can only produce children of AB, A and B bloodtype. There will not be able to produce a child of O bloodtype in an of the cases above.