What is the tender rule in real estate law?

We also recognize that this tender rule is not absolute and courts have discretion to excuse the tender requirement when its application would be inequitable. (Onofrio v. Rice (1997) 55 Cal.App.4th 413, 424.) For example, "'if the action attacks the validity of the underlying debt, a tender is not required since it would constitute an affirmative of the debt.'" (Ibid.)⁶ Here, appellant is not attacking the validity of his underlying debt. Rather, appellant argues that tender is not required because (1) he "does not seek to set aside a completed foreclosure sale;" and (2) he does not seek to quiet title against a mortgagee but against "entities who are falsely claiming to be the mortgagee."