AI (or more accurately, machine learning (ML)) learns by being told when it’s wrong and right (like a child). The AI makes a mistake on what 2+2 is, so it’s corrected. However, when it’s asked 2+3, it doesn’t know that 3 is one more than 2, and the only answer it’s learned is 4, so it says 4.

As is well known, a child learning language will often initially assume that rules/patterns are more regular that they actually are.

The ai was trained that the answer is 4, so the second time around it went with 4.