I think it shows return(GSTR-3B) status of  counter party.

As because when we download the GSTR-2A in excel format it is clearly written "counter party return status"

Further name of GST-R1 as per GST Law is "statement of outward supply".

The one possible reason is,it shows status of Payment of Tax on that supply. As because secton 16 of CGST Act has 4 conditions to avail credit, and it includes the condition of "return(or statement) has been filed and tax has been paid by supplier on the same".