Cal. Prob. Code § 2110

Unless otherwise provided in the instrument or in this division, a guardian or conservator is not personally liable on an instrument, including but not limited to a note, mortgage, deed of trust, or other contract, properly entered into in the guardian’s or conservator’s fiduciary capacity in the course of the guardianship or conservatorship unless the guardian or conservator fails to reveal the guardian’s or conservator’s representative capacity or identify the guardianship or conservatorship estate in the instrument.