Lambda doesn't insert RDS MySQL when called from Step Function

I have a Lambda function that inserts to an RDS MySQL database. It works fine when I test the Lambda function, and I can see the database immediately has the new inserted information.

But when I run my Step Function, which calls this same Lambda function, the new information is never added to the database. There are no errors in the Step Function and the input/output to the Lambda is as expected, and appears to have run smoothly and inserted to the database. But I don't ever see the new database rows. Any thoughts on what I might be missing here?