Issue with Transfer to Phone Number - External Attribute and Lambda

Hello,

Trying to set up a scenario, where an external number is grabbed from a Lambda function and then transferred to a phone number.

In transfer to phone number Contact Flow block, I have it set as Use Attribute, Type External, then $.External.Address and I've logged it and it successfully is getting the number from Lambda, but when I check the log in CloudWatch there is a period (.) appended in front of it.

Ex: "ContactFlowModuleType": "Transfer",
"Timestamp": "2020-06-28T00:14:03.276Z",
"Parameters": {
"BlindTransfer": "false",
"PhoneNumber": ".+15555555555",
"TimeLimit": "30"
}

When it gets the attribute from the Lambda function it does not have the . in the ExternalResults.

Example from CloudWatch logs:
"ExternalResults": {
"Address": "+15555555555"
}

The Transfer is initiated but my test phone doesn't receive the call, and the phone I'm calling from disconnects.

Any ideas or suggestions on formatting would be great, been using this doc https://docs.aws.amazon.com/connect/latest/adminguide/connect-lambda-functions.html#process-function-response to guide me and the Lambda function is in Python.