A more thorough explanation:

The tender-back rule is a legal principle that applies to waiver or release agreements in an employment context. It requires an employee to return any consideration received from an employer if they wish to litigate any issue that was supposedly waived.

An employer offers a severance package to an employee with an agreement stating that acceptance of the package waives all of the employee's rights to future claims against the employer. If the employee decides to sue the employer for a claim that was supposedly waived, they must return the severance amount received before commencing the lawsuit.

The tender-back rule is commonly used as a defense by employers to prevent employees from taking the benefit of the agreement and then pursuing additional compensation through litigation. The rule imposes an obligation on potential plaintiffs to return any consideration received before commencing any claim or counterclaim.

However, the tender-back rule does not apply to all claims. For example, claims brought under the Equal Pay Act (EPA), Title VII, and Age Discrimination in Employment Act (ADEA) do not trigger the tender-back rule, and plaintiffs asserting violations of these acts do not have to return any consideration to commence litigation.

In summary, the tender-back rule requires an employee to return any consideration received from an employer if they wish to litigate any issue that was supposedly waived.