Section 604 - Limitation on action contesting validity of revocable trust; distribution of trust property(a) A person may commence a judicial proceeding to contest the validity of a trust that was revocable immediately before the settlor's death within the earlier of:(1) three years after the settlor's death; or(2) four months after the trustee sent the person a copy of the trust instrument and a notice informing the person of the trust's existence, of the trustee's name and address, and of the time allowed for commencing a proceeding.(b) Upon the death of the settlor of a trust that was revocable immediately before the settlor's death, the trustee may proceed to distribute the trust property in accordance with the terms of the trust. The trustee is not subject to liability for doing so unless:(1) the trustee has actual knowledge of a pending judicial proceeding contesting the validity of the trust; or(2) a potential contestant has notified the trustee in writing of a possible judicial proceeding to contest the trust, and a judicial proceeding is commenced within 60 days after the contestant sent the notification.(c) A beneficiary of a trust that is determined to have been invalid in whole or in part is liable to return any distribution received to the extent that the invalidity applies to the distribution.