I found the issue today.
We had initially been using AWS Data Migration Services for the table in question. It auto created a column of Numeric(38,10). DMS did this for ALL Oracle columns with a data type of NUMBER. We did analysis on the source data (which is just Oracle NUMBER with no precision) and didn’t see any examples of non-integer data. We converted that column to a numeric(18,0).
Job ran for days with no issue and then suddenly failed…column 9, row x was truncating.
I opened up SSMS and did a generate create table script. Column 9 in the list was Numeric (18,0) as mentioned.
I queried the source table and found 1 row with decimal data. I modified my target column and now the job works.
I wish it was easier and we got better error messaging. It would have made things quicker.