Until a transcript of the record in a case shall have been filed in a court as hereinafter provided, the board may at any time, upon reasonable notice, and in such manner as it shall deem proper, modify or set aside, in whole or in part, any finding or order made or issued by it: Provided, That any agreement made between an employer and a bona fide employe organization, and all the provisions thereof, shall be entitled to full force and effect unless the board specifically finds that these provisions involve the commission of an unfair practice within the meaning of Article XII of this act.¹