What is the authenticity of the saying, "He who says 'I don't know' has issued a fatwa," or "He who says 'no' has issued a fatwa," and what is the reason for its occurrence?

Whoever says "I do not know" or "I am not aware" has issued a fatwa, meaning that the person being asked informs the questioner that he does not know the ruling on the matter, and that the questioner should ask others among the people of knowledge. It does not mean that the one who said that has given the questioner a fatwa in response to their issue.