Same VPC/region data transfer cost from lambda to ec2

See below from the VPC FAQ

Below is discussing Endpoint ENI but concept is the same for Lambda also because Lambda also spins up an ENI.

Q. Who pays the data transfer costs for the traffic going via the interface-based VPC endpoint?

The concept of data transfer costs is similar to that of data transfer costs for EC2 instances. Since an interface-based VPC endpoint is an ENI in the subnet, data transfer charges depend on the source of the traffic. If the traffic to this interface is coming from a resource across AZ, EC2 cross-AZ data transfer charges apply to the consumer end. Customers in the consumer VPC can use AZ-specific DNS endpoint to make sure the traffic stays within the same AZ if they have provisioned each AZ available in their account.