BigQuery - quoting strings produced unexpected results

I am running the following query:

select concat('{','"name"',':', chr(34), str,
              chr(34), ', ','"type"',':','"string"','},') jsonl
from (select 'part_number' as str)

which results in:

and this is the expected results.

But when I save the results to a csv file, the results look different.

The issue is with the extra double quotation mark that is surrounding each element.

Any idea what is causing this discrepancy.

btw, my local machine is running Windows 11.