As per Section 37, details of inward supply of the recipient should match with the outward supply declared by the supplier for the current tax period or for the earlier tax period. In this case, the inward supply of the recipient is filed for the period September 2017 and will match with the outward supply of the supplier filed for the period August 2017.
(ICAI FAQ PUBLICATION 06-09-2017 -: Returns : FAQ NO. 13)