Mastering language is difficult for humans. I don't think most people realize how often they just guess at meanings, and how often they are wrong. Especially in spoken language.

Constantly asking for clarification is exhausting and gets you labeled as pedantic and "difficult". So most people don't do it. I'd guess that a fairly high percentage of human communication results in a misunderstanding. This is largely masked by human inaction or ability to disguise their lack of understanding. The AIs have no ego and no incentive to hide their confusion.