Misfeature

He hath his Winter too of pale Misfeature, / Or else he would forego his mortal nature.

This may not appear to be a critical misfeature, and in fact I have on occasion come to rely upon this unintentional archive of data to recover the data[…]

Most recent research on modern open source codebases indicate that array covariance is extremely rarely used and is almost certainly a language misfeature.