Cal. PROB § 4155

(a) Subject to subdivision (b), the authority of an attorney-in-fact under a nondurable power of attorney is terminated by the incapacity of the principal to contract. (b) An attorney-in-fact or third person who does not have notice of the incapacity of the principal is protected from liability as provided in Chapter 5 (commencing with Section 4300). (c) This section is not subject to limitation in the power of attorney.