Previous year invoices missed

mukund (manager) (480 Points)

18 October 2019  
I have shown the forgotten sale invoices of fy 18-19 in Gstr 1 of Sep 19 . My question is that should I add this forgotten amt of fy 18-19 to the sale of Sep 19 in Gstr 3b, if I add then sale of 19-20 will be mismatched .what to do?