What is the Attorney General's argument that failing to instruct on the issue of joint possession is forfeited or invited?

The Attorney General argues that any purported error in failing to instruct on the issue of joint possession was forfeited or invited. "'[W]hen a defendant presents evidence to attempt to negate or rebut the prosecution's proof of an element of the offense, a defendant is not presenting a special defense invoking sua sponte instructional duties. While a court may well have a duty to give a "pinpoint" instruction relating such evidence to the elements of the offense and to the jury's duty to acquit if the evidence produces a reasonable doubt, such "pinpoint" instructions are not required to be given sua sponte and must be given only upon request. [Citations.]'" (People v. Saille (1991) 54 Cal.3d 1103, 1117.) Unless there is a sua sponte duty to instruct, a defendant waives any error in failing to instruct where defendant does not request the instruction. (People v. Hawkins (1995) 10 Cal.4th 920, 952.)