There are directors/executives that sit on compensation committees that also wind up deciding their own pay. And if you decide your own pay it isn't much of a leap to also decide bonus amounts and criteria.
Some quotes: waive a shareholder’s right to sue the directors for violating their duty of loyalty regarding setting their own pay and For directors setting their own pay, the ruling suggested that a blanket waiver etc.
Here's an article from Harvard Law Review about a lawsuit over this - you might be interested in the paragraphs in the "Shareholder Waivers" section: https://corpgov.law.harvard.edu/2019/09/18/setting-directors...
Some quotes: waive a shareholder’s right to sue the directors for violating their duty of loyalty regarding setting their own pay and For directors setting their own pay, the ruling suggested that a blanket waiver etc.