Tax Free Purchase Figure missed in GSTR 3B

Dear Experts

Please clear my one doubt , In the case of a Registered Dealer the Monthly GSTR 3 B for the year 2022-23 have been submitted but in Some months TAX FREE purchase was there but these figures have not been submitted

This lapse is in some of the months GSTR 3B , not in all Returns..Whereas Nil rated Sales has properly been incorporated in all Returns

The Total Sales Turnover of The Dealer is around 3 crores..How this mistake can be corrected in Monthly GSTR 3 B of September 2023, which is yet to be filed..

Please Guide me properly, Thanks