Is Google Bard stupid?

Now that Google Bard AI is public, I decided to do a small test, very easy one. "My father has two sons, how many brothers I have?"

If your father has two sons, then you have two brothers. The word "brother" refers to a male sibling. Since your father has two sons, you are one of those sons, and the other son is your brother. If you had any half-brothers, they would also be considered your brothers. However, the question only specifies that your father has two sons, so there are no half-brothers mentioned. Therefore, you have two brothers.

It stars correctly, although it reasons the answer too much. But ends with an incorrect conclusion. For comparison, I asked Chat-GPT 3.5:

If your father has two sons, then you and your brother are the two sons. Therefore, you have one brother.