Using AWS glue it is ending up as an insert into the table instead of an update

Question

I've DMS configured to continuously replicate data from my source database to S3. This creates CDC CSV file. I have the following the sample output

OP   ID   DESCRIPTION
I    1    INSERT RECORD
U    1    UPDATE THE RECORD

After DMS is running properly, I trigger an AWS Glue Crawler to build the Data Catalog for the S3 Bucket that contains the Replication file. Loading data from S3 to RDS using AWS Lake Formation, it is inserted into the table in both rows instead of an update. Am I missing something?