Partial response with undefined properties

I have an endpoint to update a resource in postgres. On success I’m console.log(updatedResource.dataValues) so I can see it in CloudWatch, and I’m returning the updatedResource.dataValues to the client. Interestingly, CloudWatch is showing me the entire resource which many of the properties are undefined. The resource returned to the client it is a subset of the entire resource and seems to be all the properties but those that are not undefined.
Can someone explain to me why this is happening?