Interest on Late payment of GST

MY Indians Tv (292 Points)

18 November 2020  
this case is relevant to Fy18-19.

Say for Jul'2018, I've paid the amount of tax due for that month before 20th Aug(i.e, due date for July) and the gstr 3b has been filed on 30th.

I've received a notice asking me to pay interest from 20th to 30th? Is it justified?

Do I have to pay the interest for that 10 days though I've paid tax within due date?