Gst 3b filed on due date but still late fee message showing

[Shan S]

on 20th dec 3b was filed and payment made 4 days prior to filing. 

But while filing, there is a gap between submission and filing, late fees will be applicable in next return. Can you someone enlighten why this is coming?

20th is the due date for monthly return no? what should i do? 

AI Summary

GST GSTR-3B filing triggers automatic late fee if final "FILE" action occurs after the portal's internal due-time.
Late fee arises because GST treats a return as filed only when the taxpayer clicks "FILE" with EVC/DSC and the portal computes delay against an internal cutoff that may treat the due date as beginning of the calendar day; earlier tax payment or submission does not prevent automatic late fee entries. If the portal incorrectly records delay, taxpayers can lodge a grievance with the Common Portal Grievance Redressal Cell or approach the jurisdictional GST office to seek reopening and rectification.