Oregon Revised Statutes Remedies and Special Actions and Proceedings § 36.460

(1) A party who knows that any provision of ORS 36.450 to 36.558 or of any requirement under the arbitration agreement that has not been complied with and yet proceeds with the arbitration without stating an objection to such noncompliance without undue delay or, if a time limit is provided for stating that objection, within that period of time, shall be deemed to have waived the right to object.

(2) For purposes of subsection (1)  of this section, “any provision of ORS 36.450 to 36.558” means any provision of ORS 36.450 to 36.558 in respect of which the parties may otherwise agree.