What is the error on the back of a 1970 quarter?

Excuse me, could you elaborate on the specific error that is reportedly found on the reverse side of a 1970 quarter coin? Are you referring to a minting error, a design flaw, or perhaps a unique feature that stands out from other quarters of the same year? Understanding the nature of this error would be essential in providing an accurate description. Is there a particular aspect of the coin's design, such as the eagle's depiction or the inscriptions, that seems to be at the center of this question? Additionally, is there a specific reference or source that you've come across that highlights this error, as it might help in providing a more detailed answer?