Enhanced demand u/s 143(1)

1) Filed my return on 31/07/2023. As there was delay in payment of Advance tax the field for 243(B) and 243(C) got auto populated and the amount payable shown was paid in full. Now on 3rd August received a mail regarding ITR intimation with the header " You have a Demand for A.Y. 2023-24." The demand was for interest on delayed payment by Rs 3866. When I was filing the return in July, the field for 234(B) got auto filled with the amount 876. The full demand was paid and after that when it was shown tax payable as nil, the return was filed. Now the demand is raised by Rs 3866. Under the column 'Tax provided by taxpayer' the amount is shown as Rs 876 ( Though it was auto-filled and not provided ) whereas the column 'as computed u/s 143(1), the figure is 4761. Hence the difference of Rs 3886 which is the demand.

2) Another issue is, as Advance tax I paid Rs 77000 on 31/03/23 under minor head 100. The challan was also generated for this. Now the statement under intimation 143(1) shows advance tax as nil. This amount is showing under self assessed tax under minor head 300.