Why does the problem "Invalid value in column 2 for type Int8" always exist when running ads integrator although the data type is varchar (not integer)?

Hi everyone, wish you have a happy new year.

I have had a big problem when working with ADS Integrator and now I still cannot fix that problem. I have been stuck with this for 2 days. The problem is “Invalid value in column 2 for type Int8” with the column that has a varchar type (not integer or numeric data type).

More specific, I have a csv file with the name ip_address_string_new with 6 columns, and all columns I have modified it with varchar data type. When I run csv downloader for this csv file, it still runs successfully and nothing happens. But when I run the ADS integrator, the errors folder appear with the ip_address_string_new rejected file and ip_address_string_new exception file. In the  ip_address_string_new exception file, it said that “Invalid value in column 2 for type Int8 - '' len 0” like the image below

And In the  ip_address_string_new rejected file, there’re some records like the image below. It said that in the column 2 in each record, the ADS Integrator cannot convert the value null into the type Int8, but I just don’t know why this problem appears because I have config the data type for all columns of this file is only varchar. So why ADS Integrator need to convert the value to integer data type?

I have tried many ways by adding some options like replace null value with value “123” by null_value, adding escape_as field or enclosed_by field or remove those adding options but it doesn’t make sense.

Those records below are the records that have been rejected

Here is my metadata for the ip_address_string_new

Please help me fix this or just give me a hint about this. Thank you guys. I really need your help.