Cal. Probate Code § 18104

(a) If an interest in or lien or encumbrance on real property is conveyed, created, or affected by an instrument in favor of a person in trust but no beneficiary is indicated in the instrument, it is presumed that the person holds the interest, lien, or encumbrance absolutely and free of the trust. This is a presumption affecting the burden of proof. In an action or proceeding involving the interest, lien, or encumbrance instituted against the person, the person shall be deemed the only necessary representative of the undisclosed beneficiary and of the original grantor or settlor and anyone claiming under them. A judgment is binding upon and conclusive against these persons as to all matters finally adjudicated in the judgment. (b) An instrument executed by the person holding an interest, lien, or encumbrance described in subdivision (a), whether purporting to be the act of that person in his or her own right or in the capacity of a trustee, is presumed to affect the interest, lien, or encumbrance according to the tenor of the instrument. This is a presumption affecting the burden of proof. Upon the recording of the instrument in the county where the land affected by the instrument is located, the presumption is conclusive in favor of a person acting in good faith and for valuable consideration.