"Reason" and "Source" Attributes for a Lead's Activity Simply Say "Web Service API"

[#1]

Issue

Issue Description
When a lead is created through an API call, the Reason and Source attributes say "Web Service API" with no further detail.

Solution

Issue Resolution
As described in the doc here, https://docs.marketo.com/display/DOCS/Understanding+System+Managed+Fields, "Source" and "Reason" fields are managed by Marketo:

1. Web Service API for Original Source Type means Person was discovered by a web service API.
2. For Registration Source Type, it states that Person was created via SOAP/REST API

When a lead is created via API, no additional "Source" or "Reason" is provided to Marketo.

A possible workaround is to create a custom field and populate it as needed through the API.