Why are non-GST supply amounts not showing correctly in my GSTR-B returns?
Check few possible reason below:
1 : It is important to ensure that all non-GST supplies are properly recorded in the software to reflect accurately in the GSTR-3B returns.
2 : Check that you are specify non gst tax category in item master or not
3 : You can check invalid tax in voucher of gst audit report. and then made the change