PROB §16464: (a) Except as provided in subdivision (b), a beneficiary may be precluded from holding the trustee liable for a breach of trust by the beneficiary’s release or contract effective to discharge the trus

(a) Except as provided in subdivision (b), a beneficiary may be precluded from holding the trustee liable for a breach of trust by the beneficiary’s release or contract effective to discharge the trustee’s liability to the beneficiary for that breach. (b) A release or contract is not effective to discharge the trustee’s liability for a breach of trust in any of the following circumstances: (1) Where the beneficiary was under an incapacity at the time of making the release or contract. (2) Where the beneficiary did not know of his or her rights and of the material facts (A) that the trustee knew or reasonably should have known and (B) that the trustee did not reasonably believe that the beneficiary knew. (3) Where the release or contract of the beneficiary was induced by improper conduct of the trustee. (4) Where the transaction involved a bargain with the trustee that was not fair and reasonable.