I was doing similar things using a data conversion and I got similar error messages. I want to report what I think is a bug in ssis. I was reading a .csv file to a data conversion and then assigning it into a decimal(18.8) ms sql column. All fields in the .csv were enclosed in double quote ("). The double quotes were removed before assignment to the database. The Data Conversion step assigned the problem column to a dt_numeric 18, 8 value. This wasn't easy to find in 180k row input file but a row with "0" in the numeric column was causing the problem. If I removed the row with the "0" it worked. If I changed the row to 0.0 it worked. If I changed the row to "1" it worked. That to me that is a bug in ssis. I can replicate this problem any time with a vs 2019 built ssis package in our environment.