GSTR1 - INCOMPLETE INVOICES PUT IN

Hope you have paid the tax for those missed invoices in GSTR3B. If yes, as of now there is no other option other than adding in next month/quarter. But you cannot add it with date prior to current month/quarter. So you can add it by putting a date in current month/ quarter.

If you have not paid tax for those invoices in GSTR3B, then pay it in current month GSTR3B and add it in current month/quarter GSTR1 return.

This is the only practical possibility. 

Since tax is paid correctly in the respective months there might not be any issue. However its still incomplete return. Hence the final stand is what the Tax Officer takes.